We befriend people with whom we spend time. As simple as that. Usually that happens because you have common interests, common foes, and/or common values, but those are a non-problem in college where everyone is facing the same issues, are roughly of the same age, and still have to develop a strong set of beliefs.

So, to get practical, I would suggest: just show up. Show up in class, show up at clubs, show up at extra-curricula activities. Do it long enough, be honestly engaged, and you'll be surrounded by friends you'll keep for all your life.