The following tips have been adapted from www.emilypost.com 
You're moving into a room smaller than your closet at home— and you have to share it with someone you've never met… Welcome to college! Tips on getting along in 144 square feet or less.
Other than a spouse, there is probably no other person in the world you will get to know as well as your roommate. Even if you bond instantly, there may be moments when your roomie's little quirks get on your nerves. Letting things fester (in that tiny little space) can turn an annoyance into a misery. Communication - both talking and listening - will be the key to a great relationship.
Less is more. By the time you've managed to fit in two beds, a computer, CD-changer and TV, will there be any room for clothes (not to mention a few books??) There is no way you are going to duplicate all the comforts of home. The less you bring, the less you have to keep track of and maintain.
Rule #1: Don't.
Rule #2: If you absolutely must borrow something, always ask permission first. Return it in the promised timeframe and in the condition it was in when borrowed. If you damage or lose something you borrow, you are responsible for replacing it. Can't afford to replace it? See rule #1. Nothing causes more strife between roommates and friends than borrowing - money, food, clothes, CDs, and sports equipment.
If the law of averages works, one of you will be extremely neat and the other extremely messy. Here is where you learn the great art of communication and compromise. Mom doesn't live here, but you do. The neatnik will have to learn to tolerate life's imperfections. The slob, well, it's time to start picking up after yourself.
It's inevitable. One of you will have an 8 a.m. class and the other will want to study until 2 a.m. Work out routines for late night studying (is there a lounge?), late night returns (tiptoe and use a flashlight?), and early morning classes (tiptoe out and dress in the bathroom?). Everyone needs their zzz's.
Most residence halls have quiet hours. Loud music, parties, or socializing in the hall will not be appreciated by your fellow corridor-mates and are a one-way ticket to unpopularity.
When the course of rooming does not run smooth, seek counsel. Your floor will have an RA (Resident Assistant) who is usually an upper-class student. Note each hall has a manager who is trained to provide you with the appropriate avenues of support.