Get a train card installed on your phone ASAP. This is way more convenient than pulling out your wallet everytime and adding money is way easier.
Don't pack too many shirts/shorts. Japan is cold in the fall semester and coming from Hawaii means you won’t be wearing them anytime besides the dorm.
Join a club. Every student here has said they wished they had more Japanese friends/have a hard time making Japanese friends. Clubs are the easiest way to have fun while meeting Japanese people.
Go out alone. Many of my opportunities to do things I wanted were stopped by me trying to find a group to do it with. There is nothing wrong with going out with yourself.
Take culture classes. These classes have been my absolute favorite here in Japan because I am learning about my experiences in a meta way. I am learning how I am learning.
Connect within your dorm. Everyone is in the same situation and before people settle into groups you should be trying to mingle and mix.
Don’t be afraid to mingle with different people. An exchange is meant to be uncomfortable and what better way to get over it than to jump into it head on. Try and meet people you would not normally meet.
Cook. While you may not always find the ingredients to make dishes you like, everyone is adapting and the kitchen is a social hub.
Enjoy the exchange rates. The dollar has crazy power now and it means that everything is a bit cheaper than back in Hawaii. Just don’t go too crazy.
Be open minded. Everyone here is from a different place with different views of the world. What you might think is rude may be normal for someone else. Something you perceive as rude/mean might be that person's normal.