As the US you don’t need a lot of transports and ground troops in the pacific. This automatically gives you an advantage over Japan as they have to balance naval and troop/transport purchases in order to hold all of their territory.
To beat Japan you simply have to sink or contain their navy. Easier said than done, but focus getting up to at least 3 carriers. Some players like to match battleships with the IJN as well. They main strategy is to have a large disposable stack of submarines as America. At least 10+ in the Pacific with about 5+ destroyers.
While you don’t have fleet superiority, never park your fleet in range of Japan’s. As a Japanese player as soon as I see the US muscle up a fleet to somewhere like the Carolines or Queensland and I know I can wipe them out I will not hesitate.
Peel off 5+ subs if Japan splits off their fleet at any time to cover transports for the DEIs. The more fractures for the fleet you cause the more they will feel the pressure to rebuild. You should have a steady stream of destroyers and submarines flowing from Hawaii. A large destroyer/sub purchase moved to Hawaii makes it hard for Japan to build new fleet out of SZ6 without risking a suicide strike. US Submarines are the worst because that means each new fleet purchase needs at least a destroyer.
ANZAC with 2-3 subs at any time is also a thorn for Japan since they can strike Japanese navy sitting near the DEI. I’ve seen some devastating hits on Japan with a US player suiciding subs/destroyers into a split fleet and ANZAC sending 5+ subs after to clean up and take out any tipped carriers/battleships.
Capital ships are nice, but once you have 3-4 carriers and 2 battleships, works on getting two solid stacks of destroyers and submarines for cover.
And lastly, remember that Japan’s hardest task is putting their fleet in an operable position while still defending SZ6 from US convoys. The nice thing about Japan being in SZ35 or SZ36 is that they aren’t close enough to hit Hawaii. That means if you send 10 submarines at whatever Japan buys in SZ6 they can’t exploit that by counterattacking your reduced Hawaii fleet, and reinforcements for you are only 1 turn away if they move up to try to counter-hit you.