Socializing is easy, if your remember a few simple rules.

1) Humor is welcome everywhere, use it. Just make sure the humor is appropriate for the social circumstances.
2) Do not talk about yourself unless asked. Nothing is more boring than listening to someone go on and on about themselves. You can interject your own experiences into a conversation, but keep the focus of the conversation on the subject. Note that you should not stop other people from talking about themselves, particularly women. While it may be boring, your objective is to be a good conversationalist, not to be entertained.
3) Make it clear that you are paying attention to what the other person is saying. Body language (i.e. nodding your head) is useful, but nothing is better than asking questions. It is very easy to use a question to get more information out of a person, and it's easy to come up with questions. Pick a specific thing that the other person just talked about, and ask for more information about it or probe deeper in another fashion. This makes the other person feel like you are interested in what they are saying, and it lets the other person do most of the work while still giving you credit for being involved.
4) Beware discussing controversial topics (i.e. politics, religion, etc.) until you know exactly how the other person feels about them. It's bad form to get into a controversial discussion during an otherwise casual conversation unless its with a close friend. If the other person goes down this path, redirect the conversation away from the point as best you can. Agree with them where possible, say that you understand that point of view where possible, but never ever disagree.