Seems contrary to our last tip, right? Let me explain. While it's important to speak up when you're roommate is bugging you, it's also important to pick your battles. If you're always nagging your roommate about something, they'll tune you out when you have an important concern. So yes, speak up if something really bothers you, but also learn when to let things go.
If you hate your roommate's music, rather than complain every single time he turns it on, put on some headphones. A mountain of dirty underwear that's left to stink for weeks is worth bringing up, while a stray sock on the floor is not. Know what you can and can't live with, and be prepared to let some of the other things slide. After all, your roommate is probably letting some things you're doing slide, too.
And, if you find that living with your roommate is simply unbearable, buck up. It's only one school year.