Summarize the following:
The worst thing at a frat party is to go overboard on the clothes and look like you're trying way too hard to fit in. You want to stay classy, but wearing a tuxedo will most likely get you laughed out of most frat parties.  If you're a man who is unsure what to wear, a polo and jeans or a button up shirt and some slacks will suffice. Just make sure your clothes aren't wrinkled or have any stains and you'll fit in. Girls can wear skirts, a dress, or jeans, but just make sure that the skirt isn't too short and the dress isn't too long. Frat parties can get crowded and a long dress can get dirty very easily, and there's a good chance there will be people physically bumping into you. Keep the weather in mind. No one looks cool when they are shivering from the cold, or soaking wet from the rain, so try to dress appropriate to the weather forecast. If you already have a unique style, stick to it! The thing that matters most about how you dress is how confident you feel about your appearance. If you smell bad or look dirty, people are not going to want to interact with you at a frat party. If you've spent all day in the heat or doing something physical, it's important you wash off the dirt before going to a party.  If you don't have time to shower, make sure to apply some cologne or perfume. Keep in mind that this is not a substitute to good hygiene. If you feel anxious about being around a ton of new people, it's good to loosen up at home with your friends before you go out by having a couple drinks if you are over 21. This will get you in the mood to be social, and will make your experience better once you get to the party.  Don't go overboard on drinking. Showing up to a party totally drunk is bad form, and they could restrict you from going in! Once you are at the party, getting too drunk can tarnish your reputation and be very dangerous.

Summary:
Wear clothes that are comfortable but trendy. Take a shower before you leave. Loosen up with friends before the party.