Caring what other people think... how do I stop?

I know what you mean I did the same thing when i started out at work but the thing is that you have to keep reminding yourself that people have too many important issues that they have to deal with than to keep their thoughts on you. Think about it, do you judge every person that walks into your work? chances are you don't even remember them. Just open up to people and show them "you" its not as hard as you think, maybe they are shy or think that you think they are stupid or you don't like them as well.