Be a friend to yourself. Not in a sappy, metaphorical way, but in a game-theoretical way. One of the mistakes I made for the longest period of time was that I waited for other people to make the first move. If someone didn't regularly go out of their way to interact with me -- come over and talk to me, invite me to do things -- I assumed they didn't want to and didn't go over and talk to them or invite them places.
This was a terrible strategy: if I met myself, I would never become friends with myself because neither of me would make the first move. Fortunately, I encountered enough forward people that I still ended up meeting some folks, but there are a lot of people I could have been friends with but am not, just because both of us were too shy.
So make the first move. Talk to someone a couple of times, and if it seems appropriate see if they want to grab a burger or see the new Hobbit movie at midnight when it first comes out. And then don't be pushy; if you make a couple of advances and they don't reciprocate, back off. Be polite and friendly, say hi in the elevators, and make small talk if they seem to like small talk. Not everyone is meant to be friends with everyone else.