There are several ways you can deal with your roommate if you are having issues with him or her. I am going to be talking about if you are a guy but I feel like it will work for both genders.
You can talk it out, yes this may seem a little weird at first and may cause some conflict but hey its a part of growing up. The best time to do it is maybe before bed on a week day. This is when you two are both relaxed and don’t have much going on. This is the best option I feel like because you both get whats really going on with each other. Worst thing is worst you end up moving out with him at the end of the semester.
The next thing I feel like it works is trying to bond with them. Do something with him right as school starts because at that point you are all he kind of knows at this point. Plus at the start of the school year nobody really wants to act like a jerk to someone else because you never know who you are talking to.
Finally I think you should and this is last resort is talk to the RA. I saw this is last resort because you don’t want to look like you will tell on people on the floor. I know its not your intention but it sometimes does look like that when you walk into the RA’s room.
Overall, I think that more often than not you and your roommate do become best friends or just become friends. I have never seen in two years in the dorms seen someone hate someone because they were roommates. If the guy is being a dick to you (sorry for my language) then talk about it, it will work.