I can tell you how to stop being a quiet guy, but prepare not to be like by everyone, and that is usually the worst fear people with social anxiety have.
Talk about the things you like, and start conversation about the things you like, you are passionate about. If everyone around you don't share your interest guess what, find some people that do. Maybe you share the same type of humor? For example, I have sarcastic humor, like Chandler from Friends if you've watched. There are a lot of people I piss of with that, and we just don't get along, but the ones that are cool with that, that like to have fun the same way, we get along just perfectly. So, maybe you share the same type of humor with someone, maybe you watch similar tv shows, movies, maybe you like the same type of girls...
You need to open up yourself, find out what YOU like, what YOU want to do, and show that to other people. When you do that, you will find people that have similar interests and you won't be the quiet guy anymore. Another example, I like bowling, tennis, basketball, salsa...when I want to go there I invite people..we share the same experiences and because of that we have smth to talk about.
Don't try to be friends with everyone, don't try to be liked by everyone. First, find what YOURSELF is, and than go BE YOURSELF! ;)