Flirt a little. As the party progresses, flirt a lot. Don't end up alone in a room with someone, though. You'll miss the party and your chance to shine. Compliment each person you talk to and find out something interesting about them.
People are most interested in themselves.
Everyone has something intriguing about them - you just may have to dig a little to find it. Don't get trapped with the same people all evening. Break away within five minutes of meeting someone and move on. You can always come back. If someone drones on and on, excuse yourself immediately and walk away.