I made afew guides previously, but now I see players still missing the most basic things, so I realize I was too "smarty" and detailed about it. I should've made a simple, beginner-friendly guide... so I'm making it now to redeem myself 
I promise this will take you from "I know the interface but not the strategy" to "I'm good at Call of War"!
Investing.
If you have resources, find a way to invest them. A good player never has many resources. And here's where to invest:
Produce as much army as possible. Only build 1 military building in each city, that's enough to start your army production right away. Don't waste any extra res to build several military buildings in 1 city. I recommend you produce out of 3 or 4 cities, but you'll need High Command to produce constantly (unless you are a 24/7 active player).
If you do this properly, you'll run out of manpower very soon (maybe even the 1st day). The remaining resources can't be used for army. So, it's good to invest them into recruiting stations, which increase manpower production. Build them in your cities first, then in regular provinces. If a province produces a material (oil/metal/goods/rare materials/food), it produces 3x less manpower, so build rec stations only in provinces that DON'T produce a material.
Also, economical buildings are only worth it in your HOME PROVINCES (the land you started with). The provinces you conquer from other nations produce 4x less resources, even if they're 100% morale; you can see that conquered provinces have darker-shaded stripes on them, so only build economy in the lighter, non-striped area (your country's starting land).
So, what about industry? If you use too much of one resource the whole game, then industry is worth from day 1 (just on that resource). But primarily use trade with other players to get res. Later in the game (when you're fully expanded), build the highest level industry possible in every home province that produces any material. I also build a massive amount of lv3 recruiting stations, because I build them even in conquered cities (only exception where I upgrade eco outside my homeland).
Strong army!
Minimize research. Start with only 2 unit types to invade your first enemies: Armored Cars and Artillery. Here's how to invade on day 1:
1. Only fight if you have much more units merged in one army than the enemy does. For example, 8 units in one army will instantly kill a 1-unit army of your opponent. The more you outnumber your enemy, the faster he will die to your damage, so he'll have less time to fight back. This is what you want: you're destroying much more enemy HP than you're yourself losing. In an infantry 8v1, you lose about 6hp but you destroy 15hp (a whole enemy Infantry).
2. Infantry and armored cars are defensive. The defender is always the army which was stationary, and an enemy army moved in to attack it. So, even if an enemy army is in your province, don't drive into it, wait for it to drive into you. This way, your army will be defending. Inf and AmCars do 1.5x more damage defending, so this is good!
3. When you invade, the enemy fights you with alot of defensive advantage: inf/AC have 1.5x more defense than attack, and units are 1.33x stronger in their home provinces on top of that! So, move in to attack if you have 6+ units against 1 enemy unit; any less favorable fight is very questionable and usually bad - still a good trade, but it isn't enough. You want perfect trades. You want to destroy everything and lose almost nothing (losing 50hp with the entire invasion is OK).
4. You're invading a PLAYER COUNTRY, which has 5 cities (50+ points in Diplomacy). Choose a weak player to invade: They haven't moved their troops, don't respond to you in diplomacy, and when you check their profile, they joined like 150 games and have only like 5 wins, and have lost more units than they have killed. That's a chronically inactive shitter who makes the game boring because he's too lazy. Invade him. If it's a new player, let him live, turn around and you'll always find a shitter to invade
5. Have three armies.
One is the armored cars (you need at least 6), invades deep into enemy territory, but only takes weak provinces. Avoid any fights other than 6v1 with this army. With the AC, your goal is to get near the 2 most remote enemy cities.
You're doing this for your second army of 8 infantry, which needs to get to those 2 cities at full HP. So, the second army walks in the first one's footsteps, reaches the 2 cities and conquers them. There should only be 1-3 enemy units defending each city, if there's more, don't step in!
The third army is the remaining infantry and 6+ artillery, which makes a slower frontal assault. With this, you destroy the large armies which you can't attack directly: if you find 10 enemy infantry sitting in one city, bombard them with 6+ artillery and 10+ infantry in front. If the enemy reacts and moves against your artillery, just let him walk into your 10+ infantry (do NOT move!) This way, his army will be "Attacking" and yours "Defending", so your 10 infantry will do 1.5x more damage, and you will win. His only other option is to slowly get eaten by your artillery. But, if you foolishly walk your army into his, then HE will be "Defending", you'll lose 10 infantry and your other neighbors could easily invade you.
If your enemy hasn't even moved (this happens often), your frontal assault just walks around conquering all the provinces in the closer half of enemy land. The worst thing that can happen, is if the large enemy army is in the remote part. Then, you will have to wait for your artillery to get there. However, your opponent will usually assemble troops to the border, where your artillery assault can reach him easily.
6. Try to conquer the enemy's capital just before day 2 starts (check in the newspaper). Upon capturing a capital, all provinces you currently own get +10% morale. So, you want to capture the capital after other provinces to give them the bonus. Revolts happen at daychange, so if you eat capital just before daychange, the conquered provinces will get +10% and they won't revolt. In later game, if the enemy is tough and dangerous, do a different thing: eat capital right away. This will reduce enemy morale by 20% and you'll get all his money.
7. Also conquer small AI nations to capture more capitals! Get your home provinces' morale to 100% this way by day 2. 1 artillery + 3 infantry is enough to conquer an AI. The AI will send one unit to invade one of your provinces, so I usually keep 1 infantry waiting behind (to move into any of my border provinces if the AI sends its invasion there). I use the 2 infantry only as a shield for the 1 artillery which slowly eats the enemy's army. It can take like 16 hours to conquer a small AI nation this way, but it's cheap: I can do 1 or 2 when I'm invading a player country at the same time.
8. An enemy province gives you half its daily production when you conquer it. So, if you invade 5 cities every day, you'll get about 50% more res. That's how I sustain high army production. I also use gold to buy manpower early (day 1-3), this is by far the best way to use gold. You increase your army numbers so much by buying just one resource...
And that's it for day 1! But I was obsessively detailed on this for a reason: you can apply this through the whole game. The best invading strategy (for me) is to conquer all the weak parts of enemy territory with fast units, while my frontal assault slowly eats the main enemy army alive. That's the winning logic most players don't use: you don't first destroy enemy troops and then start conquering; you go around to conquer right away and as the enemy army is being eaten alive, you're already conquering everything. You can even ignore enemy armies if they're in irrelevant spots, like in a mountain fortress province. Isolate them there (to be eaten slowly later) and conquer everything else.
Now, as for producing army, unit types and strategies later in the game...:
- Minimize useless research. You will usually run out of manpower before other resources, so you have to spend them on something else than army. That's the right time to build economy or research. You should upgrade your units quickly, though, to be at the highest level possible! That's also why you should minimize number of unit types you use (each unit type costs many many resources to research its highest level). Upgrade your old units if they're several levels behind - upgrading artillery lv1 to lv4 is OK. Lv1 to lv2 would be a waste.
- For Axis, I often use: motorized infantry, medium tanks, artillery, interceptors, attack bombers (they're good vs ships too!) and submarines. For Pan-Asian, I use: armored cars, light tanks, artillery, interceptors. Of course this varies game to game; best is if you find a universal unit that isn't too bad vs anything (cruisers, for an unpractical example since navy is kindof irrelevant; Axis medium tanks are a better example). If you aren't active, you won't be able to use planes and artillery, so you need a massive amount of fast and strong melee units (like tanks). You can order them to fight through your enemy's entire territory, log off and hope they destroy everything (airfields, artillery batteries) before they get damaged and destroyed.
And, lastly,
Diplomacy: Be friendly and peaceful toward active players, but don't get dragged into an alliance early, better wait for the final battle to pick your side. Expand, but keep your land small and defendable; colonial empires are mostly not necessary. Stop expanding under 500 points (unless you're going Solo Victory), from then on avoid unnecessary side conflicts and prepare for the final war.
I hope I didn't forget or misspell anything, but I think I did
If anyone has a suggestion, type it in the answers here, I can edit the article and add it.
I promise this will take you from "I know the interface but not the strategy" to "I'm good at Call of War"!
Investing.
If you have resources, find a way to invest them. A good player never has many resources. And here's where to invest:
Produce as much army as possible. Only build 1 military building in each city, that's enough to start your army production right away. Don't waste any extra res to build several military buildings in 1 city. I recommend you produce out of 3 or 4 cities, but you'll need High Command to produce constantly (unless you are a 24/7 active player).
If you do this properly, you'll run out of manpower very soon (maybe even the 1st day). The remaining resources can't be used for army. So, it's good to invest them into recruiting stations, which increase manpower production. Build them in your cities first, then in regular provinces. If a province produces a material (oil/metal/goods/rare materials/food), it produces 3x less manpower, so build rec stations only in provinces that DON'T produce a material.
Also, economical buildings are only worth it in your HOME PROVINCES (the land you started with). The provinces you conquer from other nations produce 4x less resources, even if they're 100% morale; you can see that conquered provinces have darker-shaded stripes on them, so only build economy in the lighter, non-striped area (your country's starting land).
So, what about industry? If you use too much of one resource the whole game, then industry is worth from day 1 (just on that resource). But primarily use trade with other players to get res. Later in the game (when you're fully expanded), build the highest level industry possible in every home province that produces any material. I also build a massive amount of lv3 recruiting stations, because I build them even in conquered cities (only exception where I upgrade eco outside my homeland).
Strong army!
Minimize research. Start with only 2 unit types to invade your first enemies: Armored Cars and Artillery. Here's how to invade on day 1:
1. Only fight if you have much more units merged in one army than the enemy does. For example, 8 units in one army will instantly kill a 1-unit army of your opponent. The more you outnumber your enemy, the faster he will die to your damage, so he'll have less time to fight back. This is what you want: you're destroying much more enemy HP than you're yourself losing. In an infantry 8v1, you lose about 6hp but you destroy 15hp (a whole enemy Infantry).
2. Infantry and armored cars are defensive. The defender is always the army which was stationary, and an enemy army moved in to attack it. So, even if an enemy army is in your province, don't drive into it, wait for it to drive into you. This way, your army will be defending. Inf and AmCars do 1.5x more damage defending, so this is good!
3. When you invade, the enemy fights you with alot of defensive advantage: inf/AC have 1.5x more defense than attack, and units are 1.33x stronger in their home provinces on top of that! So, move in to attack if you have 6+ units against 1 enemy unit; any less favorable fight is very questionable and usually bad - still a good trade, but it isn't enough. You want perfect trades. You want to destroy everything and lose almost nothing (losing 50hp with the entire invasion is OK).
4. You're invading a PLAYER COUNTRY, which has 5 cities (50+ points in Diplomacy). Choose a weak player to invade: They haven't moved their troops, don't respond to you in diplomacy, and when you check their profile, they joined like 150 games and have only like 5 wins, and have lost more units than they have killed. That's a chronically inactive shitter who makes the game boring because he's too lazy. Invade him. If it's a new player, let him live, turn around and you'll always find a shitter to invade
5. Have three armies.
One is the armored cars (you need at least 6), invades deep into enemy territory, but only takes weak provinces. Avoid any fights other than 6v1 with this army. With the AC, your goal is to get near the 2 most remote enemy cities.
You're doing this for your second army of 8 infantry, which needs to get to those 2 cities at full HP. So, the second army walks in the first one's footsteps, reaches the 2 cities and conquers them. There should only be 1-3 enemy units defending each city, if there's more, don't step in!
The third army is the remaining infantry and 6+ artillery, which makes a slower frontal assault. With this, you destroy the large armies which you can't attack directly: if you find 10 enemy infantry sitting in one city, bombard them with 6+ artillery and 10+ infantry in front. If the enemy reacts and moves against your artillery, just let him walk into your 10+ infantry (do NOT move!) This way, his army will be "Attacking" and yours "Defending", so your 10 infantry will do 1.5x more damage, and you will win. His only other option is to slowly get eaten by your artillery. But, if you foolishly walk your army into his, then HE will be "Defending", you'll lose 10 infantry and your other neighbors could easily invade you.
If your enemy hasn't even moved (this happens often), your frontal assault just walks around conquering all the provinces in the closer half of enemy land. The worst thing that can happen, is if the large enemy army is in the remote part. Then, you will have to wait for your artillery to get there. However, your opponent will usually assemble troops to the border, where your artillery assault can reach him easily.
6. Try to conquer the enemy's capital just before day 2 starts (check in the newspaper). Upon capturing a capital, all provinces you currently own get +10% morale. So, you want to capture the capital after other provinces to give them the bonus. Revolts happen at daychange, so if you eat capital just before daychange, the conquered provinces will get +10% and they won't revolt. In later game, if the enemy is tough and dangerous, do a different thing: eat capital right away. This will reduce enemy morale by 20% and you'll get all his money.
7. Also conquer small AI nations to capture more capitals! Get your home provinces' morale to 100% this way by day 2. 1 artillery + 3 infantry is enough to conquer an AI. The AI will send one unit to invade one of your provinces, so I usually keep 1 infantry waiting behind (to move into any of my border provinces if the AI sends its invasion there). I use the 2 infantry only as a shield for the 1 artillery which slowly eats the enemy's army. It can take like 16 hours to conquer a small AI nation this way, but it's cheap: I can do 1 or 2 when I'm invading a player country at the same time.
8. An enemy province gives you half its daily production when you conquer it. So, if you invade 5 cities every day, you'll get about 50% more res. That's how I sustain high army production. I also use gold to buy manpower early (day 1-3), this is by far the best way to use gold. You increase your army numbers so much by buying just one resource...
And that's it for day 1! But I was obsessively detailed on this for a reason: you can apply this through the whole game. The best invading strategy (for me) is to conquer all the weak parts of enemy territory with fast units, while my frontal assault slowly eats the main enemy army alive. That's the winning logic most players don't use: you don't first destroy enemy troops and then start conquering; you go around to conquer right away and as the enemy army is being eaten alive, you're already conquering everything. You can even ignore enemy armies if they're in irrelevant spots, like in a mountain fortress province. Isolate them there (to be eaten slowly later) and conquer everything else.
Now, as for producing army, unit types and strategies later in the game...:
- Minimize useless research. You will usually run out of manpower before other resources, so you have to spend them on something else than army. That's the right time to build economy or research. You should upgrade your units quickly, though, to be at the highest level possible! That's also why you should minimize number of unit types you use (each unit type costs many many resources to research its highest level). Upgrade your old units if they're several levels behind - upgrading artillery lv1 to lv4 is OK. Lv1 to lv2 would be a waste.
- For Axis, I often use: motorized infantry, medium tanks, artillery, interceptors, attack bombers (they're good vs ships too!) and submarines. For Pan-Asian, I use: armored cars, light tanks, artillery, interceptors. Of course this varies game to game; best is if you find a universal unit that isn't too bad vs anything (cruisers, for an unpractical example since navy is kindof irrelevant; Axis medium tanks are a better example). If you aren't active, you won't be able to use planes and artillery, so you need a massive amount of fast and strong melee units (like tanks). You can order them to fight through your enemy's entire territory, log off and hope they destroy everything (airfields, artillery batteries) before they get damaged and destroyed.
And, lastly,
Diplomacy: Be friendly and peaceful toward active players, but don't get dragged into an alliance early, better wait for the final battle to pick your side. Expand, but keep your land small and defendable; colonial empires are mostly not necessary. Stop expanding under 500 points (unless you're going Solo Victory), from then on avoid unnecessary side conflicts and prepare for the final war.
I hope I didn't forget or misspell anything, but I think I did
If anyone has a suggestion, type it in the answers here, I can edit the article and add it. If you have above 10k manpower, you're not investing properly. A good player never has many resources.
Larger armies destroy enemies faster without taking damage from them.
Build only: 1 military building in each city, airstrips, and recruiting stations to boost manpower.
Minimize research, 2 unit types early, 6 types in late game. Upgrade old units, but: artillery lv1 to lv2 is a waste, only lv1 to lv4 is worth it.
Enjoy
Hornetkeeper
Larger armies destroy enemies faster without taking damage from them.
Build only: 1 military building in each city, airstrips, and recruiting stations to boost manpower.
Minimize research, 2 unit types early, 6 types in late game. Upgrade old units, but: artillery lv1 to lv2 is a waste, only lv1 to lv4 is worth it.
Enjoy
Hornetkeeper
