From: Florida, USA
I played about 10 months as Japan against the Allied AI using 2-day turns. My comments:
1) I learned to use TF pick-up of troops, rather than go to the port on day 1, then load the unit on day 2 (as is often the case for 1-day turns). Using pick-up at a nearby base you can often get there and start loading on day 1. When using pick-up I always set the TF to remain on station AND do not unload, because if it's a small unit it could load on day 1, then UNLOAD on day 2. The disadvantages to using pick-up are you can only load one unit per TF and, in my experience, the TF never docks, even if it could.
2) Be careful when aerial bombing enemy troops. If your ground attack on day one forces a retreat, your air units may now be attacking at extended range (so lower bomb load), or at a distance exceeding your escort's range, running into who knows what!
3) Likewise, if the LCU being attacked is destroyed on day 1, the bombers will find another target on day 2 (but your escorts will not), and 9 times out of 10 it's not one you would have picked!
4) Against the AI you play 2-day turns, but the AI plays 1-day turns, and cheats while doing it.
5) The Japanese player needs to be careful with aircraft research. If day 2 is the 1st of a month, newly researched aircraft will start production if not set correctly (ie. set to NO production). I would change to 1-day turns at the end of every month as an additional way to avoid production disasters.
6) And, obviously, atoll invasions and carrier operations in general will need special care.