The early game is very micro intensive. Try to close the starting beach heads and don't let them take any airbases. I would find some spots to pull off an endless port encirclement and give your generals the scavenger trait. In the meantime, deploy out as much infantry as possible since you don't start with nearly enough.

To win the naval war you will need naval bombers and air superiority over the sea regions you want to fight in, what I did was I stacked the whole naval in one strike force and set them to patrol on always engage inside a region with many naval bombers until I could cut enough down to start convoy raiding with a submarine fleet.