As the Allies, you need to be very patient. You need to pick away at the DEI with subs and Transports to land a few troops whenever pssible. If the Japanese player ends up owning all of the DEI when they eventually take India, the allies are done. You cannot give Japan the DEI at all costs.
As the US player, I usually send my first two fleets south towards the DEI and then send subs with bombers towards Japan to try and distract him from my southern fleet. Keep him having to split his navy, have him a little worried about Japan itself, this will also relieve some pressure off of Australia. ANZAC should build subs and hit the DEI as well whenever possible.
My buddy and I are on our fourth game now and we both feel that the game is very well balanced. First two went to Japan but Allies won the 3rd and look to have a slight edge right now in our current game. It always comes down to Australia and I learned as the allies that you have to have most of DEI by the time Japan takes INDIA. His income will be down to 55 while the US and ANZAC combined will equal close to 80. Unless he can take and hold Western Australia, I feel the Allies should be able to wear him down in 3 or 4 turns. I have a fleet heading to Japan next turn.
Great game that can go either way, depends on who makes more mistakes in my opinion.