Be yourself
Simple, be yourself. Don't put on an act, most people can see through that. Trying to remember which character you're playing today will only make you nervous. Not sure what to talk about? Act natural, talk about your interests, who you are and why your there.
Small Talk
Similar to the first point, don't write up a script and rehearse it. Make small talk. What would you talk about if you bumped into an acquaintance? The weather, something important in the news, a new course you're taking. You're interesting, trust me.
Listen
Good thing is, if your small talk fails and you seem a bit nervous, you can always ask a question and then listen. Listening is a key point to networking. Take an interest in what they're saying and ask questions. You're networking with this person for a reason, right? You want to know more! So this is your chance.
Memorable
Make yourself memorable. An interesting point, comment or even joke. Make eye contact, be genuine. If you're in a group of people, make sure you stand out. Don't get lost in the crowd while everyone else becomes memorable. If you're speaking with someone you know a little about, mention her/his company most recent accomplishment, or a project of theirs you liked. Make sure she/he leaves wanting to know more about you.
Closing Argument
Walking away is hard. When does a conversation end? When have you said too much? If you feel the time is right to bow out, say something to the effect of "I don't want to monopolize too much of your time, I'm sure there are more people you'd like to speak with." Always thank them and hand them a business card. Let them know you'd love to continue the conversation at a later time.
