Germany needs to keep buying subs and keep its baltic fleet intact. unification of Italian and German fleets is possible ( much more so than in AAR)
On G1 you need to take out british fleet, except the carrier which is too far for most of your units.
keep building a few subs and one destroyer and the rest men ( mostly) with tanks for east
also if Germany goes really strong they can prevent uk from building any ships by occupation and blockade of all sea zones.
this is much easier to do than you may think.
for Japan you need to build a larger fleet, because the Americans can build faster. That is why Japan needs the extra so they can compete an extra turn. You can also occupy the west coast sea zone and prevent Americans from building.
its basically the same idea in milton bradley edition.