Principle one: Army is what gains ground, not navy. Somehow or other, you must get armor and infantry to the mainland.
Principle two: Japan is not under immediate threat from the U.S.A. Screw defense and attack all out on the mainland for the first turn. The only exception is India, as that battle could largely go either way for now.
Principle three: The IJN can be patient, and make the U.S. come to it. After all, as long as Germany is doing it's job and you are following principle one, then you are the only force in the Orient with reliable supply lines. However, you do want to make sure the U.S. Navy isn't going to be a large problem, should the allies provide a Japan First stunt. The Pacific theater is up to you, and your evaluation of your opponent's strategy. Just make sure that if you attack the USN, attack with everything you can, and don't be conservative in buying aircraft.
Japan Strategy #1: Destroy the USN