Welcome to FT and (soon) the skies :-)
Don't worry too much about your trip and don't "overprepare". But do take a good book and a big bottle of water with you - and make sure you finish it by the time you land; it will help with jetlag. Speaking of jetlag, try to adapt to night/day times in Japan as soon as you arrive, i.e. try not to go to sleep until night time if you arrive in the morning for example.
And of course, join a FFP :-)
ENJOY!