Don't Say Anything at All
Most of the time, saying nothing will help you a lot. Just look at that episode where Malcolm from Malcolm in the Middle stopped talking and just nodded and grunted along with the conversation. Of course, you won't end up with peptic ulcer. Just let everyone else talk for you.
Never Add to the Conversation
Say you get bored of saying nothing. You could talk, but be sure to not add anything new to the conversation. By reading this article you probably aren't really good at saying new stuff. Just agree with what the others say. People often get annoyed if they want to move along to a new topic and then you just blurt something out.
Try Not to Look Uncomfortable
If your not a very sociable person you will probably look quite uncomfortable while in a conversation with others. This is very serious and you'll probably lose some of your friend's respect. If you feel uncomfortable, stuff your hands in your pockets and just look them at their ears. That way, they'll feel like your paying attention and you don't need to look at their eyes which makes most people the most uncomfortable. And remember, SMILE!
Hope this helped your social life!
