Lock your frame & front wheel to a solid object with a quality U-lock. In a low to moderate theft area that's pretty much all that's required. Basically, you want a lock that will take more than 30sec to defeat.

The biggest thing with riding a bike on campus is maintenance. Try to keep your bike parked in a covered spot to protect it from rain. Rust will kill a drivetrain in a year or less if the bike is constantly getting wet. Once every ~3-6 months take some decent chain lube and go over the chain pretty thoroughly. Once a month is better for maintenance, but I'm assuming you're a busy student, and once a semester is enough to keep a bike running through your degree.

I bought a relatively inexpensive Diamondback MTB for ~$230 in '98, used it for all of undergrad and grad school. I didn't do much to it. Kept it outside but dry, oiled the chain once in a blue moon. Only thing I had to replace was a rear wheel & tire after I bent it on curb.