Shy or silent and talk active is basic character. Some people are really shy and hard for them to change it. As long as being shy and silent has nothing to do with less self confident then I would say it is not much of problem. It is a good point for you though.... being shy makes you a bit careful with what you say. Again as long as it is not because you do not feel not confident. When you are gathering with friends, try to listen to them first, observe the situation, then you talk only when you need to. Hey... there are these people out there who do talk too much and can not shut.
You get out of your comfort zone and you keep on trying new things, it doesn't have to relate to people. Trying out new things will give you the confidence to continue trying more and more things and this will give you confidence in your abilities which will extend to your social abilities (it works for me). So go out there and do something that you've always wanted to do but were to scared of and start from there.
You try to do stuff that you would normaly not do.
You he yourself without caring what people, this way you caj set yourself with people who accet you for who you are.
Also try to join clubs, this way you can have people that have something in common with you, and meaby that can make it easier to start a conversation.