Just have fun. These games can be very long… Which is why I like to go wild in live games.
prepare to invade london with germany, remember to buy a carrier and 2 transports for the first round or carrier destroyer sub. Second round if you have not purchased a destroyer on the first, buy one and the rest transports. prepare to invade!
Have italy kill the french naval or ram into the stuff by gibraltar, because you don’t want that defending london.
Sea lion is real fast, you get london on germany round 3 or you don’t. Russia pushes in europe and you kick him out or you don’t. Simple as that.
As far as Japan goes, that is up to you. The simplest strategy is to draw an imaginary line from Japan to calcutta… and take everything along the way and the dutch islands.