Get to know your roommate. Do not make unfair or snap judgments, but take the time to actually talk to your roommate and get to know him or her.
Express your personal preferences and habits. If you like to stay up late and get up late the next morning, make sure your roommate is aware of this so that you don't have to study in the dark when he goes to bed at 10 p.m. At the same time, listen to your roommate and recognize her personal preferences.
Communicate openly with your roommate about things that bother you. Expressing your feelings now will help avoid resentment later.
Compromise with your roommate. If you always go to bed late and he always go to bed early, figure out a system that allows both of you to feel like your needs are being met.
Respect your roommate's opinions, needs and wants. If she has a big exam the next day, don't insist on staying up all night with the lights on and the stereo blasting.
Set up a schedule for study times and chore delegations. Having a schedule and sticking to it will help avoid conflicts and misunderstandings down the road. It will also ensure that study and chore needs are being met.
Resolve conflicts quickly when they arise. Do not let problems fester, since this will only lead to further complications, hurt feelings and possibly one of you moving out.
Be flexible. Being overly rigid about noise, bedtime or cleaning issues will only serve to create a rift between you and your roommate. You are individual people with distinct tastes and living styles; you can't expect your roommate to automatically conform to the way you like to live.