advice?

I'm the same way and I'm still working on this too but I can offer a little advice. Practice small talk. It sounds silly but learn how to step into a more outgoing character whenever you have the chance. Talk to new people, your friends parents, etc. I'm not saying you should be fake, just a maybe ask more questions or expand on things more (even if it does seem meaningless)

Don't try too hard. Just be yourself. If you take a sincere interest in what others are saying, and ask follow-up questions, it won't matter that you are quiet. I was worried about this, too, and I found that if things got quiet I would ask one of the questions I had thought about in advance. Things like: What's the best thing about living in the house? What are some of the more popular majors among girls in the house (or, are there lots of nursing majors, journalism majors or whatever you plan to major in). Is it difficult to get to know everyone when pledge classes are so large? Be thoughtful and non-judgmental. And, most of all, have a smile on your face and don't look bored.