Remember that people generally want to get to know the real you. Most people you meet will be just as nervous as you are. Make others feel at ease by being yourself and asking questions about the other person. As they open up to you and the conversation gets rolling, you'll feel more and more comfortable.
Remember that people are less concerned about your flaws than you are. Social situations can be overwhelming when you try really hard to be perfect. Sometimes you'll make mistakes. Even embarrassing mistakes can cause you and those around you to feel at ease if you learn to laugh at yourself. And, most people will understand if you make a mistake. They're just as intimidated.