Make sure you communicate with your roommate over the summer. Creep on over to Facebook and see if you can look them up there. If not, there’s always the phone number listed on the email with your roommate information - it may be a bit nerve-wracking, but it will help. A lot.
See if you two have anything in common. If you’re worried that you may not, see if you can gauge anything from their Facebook profile. If you find things in common, great! If not, that’s not as fun, but that doesn’t mean you need to have a bad relationship with your roommate.
Also, organizing things to bring with your roommate will help break the ice. Should you guys get a microfridge? Should one person bring a DVD player, and the other a TV? Does your roommate maybe have a rug to put down? Will someone need room for a game console?
Finally, set some guidelines for both you and your roommate to abide by. For example, your roommate may like to study in the room. Make sure you aren’t blasting obnoxious music or something while he or she is trying to do that. Also, you might like going to bed early, so see if you can set a time for loud electronics and main lights to get turned off.
Be sure to set some rules about visitors, too. Many people see their dorm rooms as a way to escape the bustling college scene. It won’t be really pleasant for anyone if you’re having a bad day and want to get away from it all only to come back to find your roommate getting lucky with his or her significant other.
Be open to communication with your roommate, and be pleasant. Adjusting to college is really hard by itself, but learning to live with a stranger is one of the worst things. Remember, your roommate is dealing with the apprehension you are. Make it easy for both of you. :)