Invade France and Spain then kill everyone else. Great strategy.

Fool around until there's one big empire in Europe, wait until they start attacking east and diesmbark, and take everything. Saves you a lot of trouble.

Navy

build a large navy, worked in RL, and kinda caused WW1


and well Britian won that so I rest my case

Also Take Ireland, and the Benulux countries fast. once you have them, you have a good place to launch an attack on Europe from

and if they attack and take that, you are still safe on the island behind a large navy

Britain is an island nation, its easy to defend with a grand navy, large air wing of interceptors, and ground units with artillery (in case the navy haven't pound the landing enemy to dust yet)

enemies will generally have a hard time invading you but that does not mean your invincible without a large navy or air force you cant possible stop a dedicated invasion force.

the Britain economy will require a lot of oil to maintain a navy so consider your non-core African possession as an extension of your country and take Iraq and other nearby AI countries for oil.

another thing is most of your industrial power is based on London and its surrounding provinces, this make organizing and defending your capital city easy but when southern Britain is lost you will either have a hard time to counter or your defeated, building up forts with interceptors and a ring of ships is mostly common on what i seen.

as for strategy wait until France is weaken or distracted and invade across the channel, from there its a good idea to take down Spain to control the Med sea and connect your off-shore territory along with some African lands from France, personally i would build up divisions of tanks and infantry units for land, interceptors and tac bombers, and a fast moving navy for both offense and defense due to being generally balance while i sit 2 battleships for my island. if you ever been beaten back you can still make a comeback for Britain is very defensible at this point, but make sure you wont drive your army units exhausted or you will lose more than what should be lost .