This Wikipedia page has some good tips:
How to Win Friends and Influence People - Wikipedia, the free encyclopedia
For more extensive information on how to feel better and more natural in social situations, this book is great:
Amazon.com: First Impressions: What You Don't Know About How Others See You: Books: Ann Phd Demarais,Valerie Phd White
I read it and it really taught me a lot of stuff I didn't know before about interpersonal dynamics and social interactions.