If you are able to, keep the bike in your dorm room/apartment. I did that freshman year, and never had to worry at night about it getting stolen. I had a relatively large single though, so work it out with your roommate. If you have to park it outside, make sure it's in a well-lit, high traffic area. That might mean parking it somewhere other than right outside your dorm room. Had I not parked my bike inside, I would have parked it at the dorm across the street. There, the bike rack was right by the entrance to a food court and computer lab, which got a lot of traffic, even fairly late into the night. At my dorm, the bike rack was behind the dorm, next to a parking lot, then an empty field, and few people walked there.
Get a solid U-Lock, and a chain to lock down the wheels. If the seat is quick-release, get a small chain or steel wire and a small padlock, and lock down the seat. Check with the campus about bicycle parking permits. My school had one, it cost $5 and registered you with a national bike registry. Also make sure you know where you can lock up. A lot of campuses will impound bikes if you don't use racks. Don't just lock to any three or sign you find.
And finally, college town drivers are some of the worst. The small streets, quirky one-way routes, and transplanting of city drivers to more relaxed country makes for unpredictable results. Keep your head up and assume the worst. Like, never assume that a one-way street won't be traveled the wrong way. Never assume people know how to work a four-way stop.