Bring a friend. College parties are often big and rowdy. You will probably meet some new people while you're there, but it's always a good idea to bring someone to talk to before the drinking games get started.
Bring a designated driver or have someone you can call to get a ride home. If no one is available, write down the phone number for a cab and keep it on speed dial in your phone for easy access if you are tipsy.
Come prepared. If you need to BYOB, bring it, or if you don't want to drink, bring some soft drinks or juice with you. Even if you are not asked to bring anything, be a friend and a good guest by bringing some drinks or snacks.
Obey the rules. Park in legal areas, keep the noise down at the party and don't provide minors with any alcohol. Getting arrested or even getting a minor citation definitely puts a damper on any party.
Meet new people. Parties are time to have fun with your college friends, but also a time to meet new friends. Be friendly, introduce yourself, and if you don't want to waste your time, learn the difference between people who want to talk and people whose inhibitions have been lowered.
Avoid a hangover by eating ahead of time, staying hydrated throughout the night, and not mixing different types of alcohol. Also avoid dark drinks like red wine and rum, which have additional hangover-inducing chemicals.
Avoid getting really drunk by alternating non-alcoholic with alcoholic beverages and not drinking more than one alcoholic drink per hour.
Watch out for your friends. You can't have fun if your friends end up sick or with a D.U.I ticket. Offer your friends water periodically, make sure they are safe if they pass out and keep track of how they are getting home when they leave.
Thank the host of the party and try to clean up after yourself. Making friends and getting invited to more parties is a breeze if you are thoughtful in addition to being fun.