How to Network as if you aren't nervous at all.
If I don't know anyone at a business event—say, a conference—I steer away from big groups and strike up a conversation with two people who are already conversing. They're very likely to welcome a third. Remember, everybody else is there to network as well. Then, if a solo person wanders by, I'll invite her in and introduce her to the others. It's a good way to hear everyone's name again.
The thing is that you're there to connect—not just hand of business cards. I like to ask people about what they do, because people like talking about what they know best. But you can ask about their families, where they grew up, whether it's family, charity, or travel, the most important thing is to get their story and hear their passions. Just put a time limit on it. If somebody's eyes start to wander around the room or the conversation doesn't come easily, it's time to excuse yourself.
If there's someone you came there to to meet expressly, do your homework. Find out their background and their interests. I'm honest about it. I'll say, "I saw this great article about you. Congratulations; can I ask you more?" Most people are flattered you took the time.
All in all, you've just got to have self-confidence. It never hurts to have a glass of wine in hand.