Do something drastic to establish yourself as the alpha roommate...just kidding.
Keep your stuff tidy
You don't have to deep clean your room everyday, but keeping your stuff out of the common space or your roommates area is the least you can do. Also, keeping your dorm or room clean makes coming back to your dorm after a long day relaxing instead of stressful.
Talk to each other
Communication is key! I know so many roommates that were frustrated with each other or felt awkward, but they never talked to each other about it and would sometimes go weeks with just barely saying hello to each eachother. It is better to discuss any issues or concerns before tension builds, and solve the problem before it really strains the relationship.
Don't be too standoffish
No need to try and become best friends the second you meet, but also don't close yourself off before taking the time to learn about each other. You may even become friends for life!
Don't be too loud
Always be considerate of your roommate and their schedule. Maybe don't blast your music at 2:00 am, unless you're trying to get on their bad side.
Ask before borrowing each others items
Whether it be food or clothes, always make sure to ask if its okay to borrow your roommate's stuff.
Hangout together
GiphyBefore you decide that you don't like your roommate, give them a chance. Go get dinner or study together, try to make an effort and get to know them on a more personal level.