im not a big party person but its my mates 18th tomorrow?!

Best Answer - Chosen by Voters

Alcohol

Make sure you say hello to your friend the instant you arrive. He will be bombarded by a lot of people, so a quick hello will do fine. Note the people who are talking to him when you greet him - those are the people you'll want to approach again after you grab yourself a drink. They obviously have soemthing already in common with you - your friend! If they don't start up conversation first, you could simply say, "So, how do you know (insert name of your friend)?" Im sure that will spur conversation. *Note: Make sure you introduce your lady!

Party-goer

Baisically, find somewhere you are comfortable in the house...kitchen, livingroom and sit down and chat to those around you about anything with a nice cold beer! And introduce your girlfriend to people, she may be more party than you and get a conversation going!

If its a disco type thing, then dont sit in the corner, get up and dance with your girlfriend, especially if the other guys are on the dance floor. Smile, be approachable and if someone says wanna dance, lets go do this...do it! unless its like drugs or smoke or something then say no!
Good luck, have fun!

take them to a club. most you can get in at 18