Have you looked up all the clubs that are provided at the school?

For example, my school is huge (39k students) and there are over 500 student run clubs. There are also various organizations that deal with ethnic groups. There are also clubs within the department where you can meet people and not everyone drinks. There are also religious groups you can become affiliated with. Even if you're not religious and just curious they should accept you. You'll most likely find people who abstain from drinking/smoking there.

I didn't drink frequently until the last year of college. I was 22 (still am) and it's usually like a beer with a friend when we're going out to dinner or something. There are plenty of people who will NOT pressure you to drink or smoke. None of my friends have been mad at me because I refused to drink.

I found that getting involved in something at the campus is a great way to network.