Combine the Allied fleets in SZ 8 or SZ 12. This should give you, with no purchases, at least 1 Battleship, 1 Destroyer, 1 Submarine, 4 Transports in SZ 12.
If you buy equipment and decide to unit in SZ 8 instead, you can have 1 Battleship, 1 Destroyer, 1 Carrier, 2 Fighters, 2 Submarines and 4 Transports between the US, USSR and UK. (With UK purchasing the Carrier and Submarine along with, say, 2 infantry on UK 1 and Russia’s submarine moved in.)
This fleet should be big enough to stop the Germans from taking ownership of the Atlantic.
Other tactics are to either go insanely aggressive with Russia stomping the Germans and trading Balkans/E. Europe with Russia or go ultra conservative with Russia forcing Germany to slow down else risk losing their tanks and artillery to Russian counter strikes.
(And yes, I’ve proven that Russia CAN hit Germany so hard that they ARE held in Berlin/S. Europe and Russia has Norway, W. Russia, Belorussia and Ukraine on a consistent basis. Not easy, but very doable and without huge massive risks being taken, just be ware that Germany will eventually be able to push Russia back because Japan’s coming up the other side, so get the English and Americans ready.)
I stand by my original arguments in other threads that England should be liberating Karelia each round, not Russia, and that America should worry about Africa, not England.