Kristin
Look for the place that makes you feel like you belong. I feel that you have the ability to be happy with your college experience just about anywhere you go. It is what you make it. Also, make sure you go to a college that is a size you are comfortable with. Make sure that your college supports and offers clubs or activities that you are truly interested in. If you can't have fun with extracurriculars, you will go crazy from all of your schoolwork! Once you find the right school, make sure you get involved with anything and everything you can. There are so many opportunities in college for things you would have never been able to do before. Stay open-minded. You will meet some of the most amazing people in your life. You will experience things that you have never been exposed to before. Enjoy it. Drink it in. It's college--and it only happens once!
Jaime
Don't judge your school on the first year - I don't think anyone liked Freshman year very much. Just be yourself and focus on where you want to be in the future and I'm sure you will make the right decision. Also, don't choose a school because someone else you know is going there.
William
There is no formula. Once you understand that each student has their own needs, and their own desires, choosing the right college for you becomes a much less daunting task. Visit each school, and talk to the students. Don't go on a saturday morning when everyone is still asleep, because no matter where you go, they will be. Ask the same questions to different people, include students, professors (if possible), and staff in your survey. Obviously the cafeteria workers won't have any clue about study abroad opportunities, but they have a valuable perspective on the student body, and social interaction.
If you haven't been thinking about social life, you should be. Think hard about what you want from your social life at school. Even if you know you won't be binge drinking on a wednesday night, your roomate might be. Your friends down the hall might be. You could be dragged into situations you'd rather stay away from, and even if you do steer clear, you'll probably spend alot of time interacting with people who won't. The general happiness of students on campus will greatly influence your experience.
It's all about experience!