There were many factors I considered but the major ones were (in no order):
1) Whether I would have to live on residence/an apartment (if the college was too far from where I live to commute daily).
2) Transportation. If I did live at home, then how would I get to campus and how much would public transport cost. If I lived at residence, then how do I get to a nearby mall for food, office supplies, etc... .
3) Reputation. This comes into effect both when applying and when receiving offers. You can get the same degree from each college but employers tend to put some weight on prestige.
4) Does the college have the programs you're interested in?
5) Diversity of programs. Many people change their minds on what they want to study. If your college is focused primarily on one particular area but you lose interest, then there's not a lot of alternate options at the campus.
6) Social life. Although you're at the college to study, you'll burn out if you don't have some social outlet, whether it be exercise, clubs, etc... .
7) Student opinions. Many websites and some magazines offer unique opinions from students but it's best to use those that are conducted across campuses, ideally through a survey.
8) Cost/tuition. This can be a major deciding factor, especially for those with high prestige.

Some things not to pay attention to:

1) Where your high-school friends are going. Chances are, even if they decide to study in the same area, you're going to meet new people anyway.
2) Where any family members went or boyfriends/girlfriends went.