**** man you've got it easy, you're still a freshman and you live in the dorms. I transferred to a large university my junior year (which was last semester), and don't even live on campus.
Anyhow here's what I do...
Ask random girls questions about the school since you're new. Like "do you know where room n245 is?"...many possibilities here.
Find an interesting student organization, join it. Then you'll have a common thing to talk about with people you don't know.
Don't joint a frat - frats are for weak pvssy *****es who can't make REAL friends and instead join a club where you pay for friends. Then you get out into the real world and realize there is no club you can join that gives you instant friends.
Strategically pick your seat in lectures. Lots of people like to have 1 seat in between themselves and the next person. To counter this, pick a seat near the END of a row, and put two seats in between you and the next person. Then late-comers always take seats close to the aisle, and will have to sit either next to you or next to the other guy. You must come early for this to work.
Alternatively, come in to class late and just keep walking towards the front till you see an open seat next to a hot girl near the aisle.
Sit near the front of the class, girls up there like to talk about class and are more friendly. Seriously.
Try to walk around campus as much as possible, it maximizes your chances of running into people from class and then allowing you to say hi to people from class you run into outside of class.
Say hi (just make eye contact as you pass them and say a friendly hi) to girls you regularly pass on your way to and from classes. If you do this consistently, eventually they will start to wonder if they know you from somewhere, and will straight out ask it. "Hey do I know you?"
I dunno that's all I can think of right now