The frat party. Yes, my favorite place to get crossfaded and hook up with girls and then forget about it until they remind me about it on campus. I'm also in a fraternity, so here are my thoughts. If you follow my advice, you'll be the princess of the ball
There are two kinds of parties - kick backs and huge blowouts. The fact people are being invited from outside of the house indicates that its a blowout. You being invited is a good sign, when I invite guys I don't know well, it's because I think they might be interested in pledging the house. This is a key point because it's the key to your frame for the night.
Repeat these words after me:
I'm planning on rushing Delta House (or whichever house it is). This isn't about just being nice to the actives, this about them taking you under their wing and them showing you a great time. You're giving yourself INSTANT higher value to yourself and to all the brothers by saying that you like what they're doing there and that you have the "good sense" of wanting in on it. If they're looking for new members, you'll suddenly find yourself being given drinks and being introduced to all of the regular girls. Stick with the guy who invited you, make sure the guys you meet know that "credit" for bringing you around belongs to him. See if the bros in the house are having a pre-party and try to get into it.
It doesn't matter if you're actually interested in pledging or not, fake it 'til you make it. I went in with this unsure attitude and I ended up joining lol. Regarding your other friend, leave him at home. He sounds like he's gonna be a total drag on you. He doesn't give you any higher value, why would you hang out with a guy who's socially awkward unless YOU are socially awkward? No, DTM, you're hot property and you have to show yourself to be.
If there's a theme, dress up for it FOR SURE. Go a little over the top and get one related super peacocky item. We had our 80's rap party and one of my more awkward bros wore a hubcap around his neck like Flava Flav. He got so much attention it was ridiculous and he didn't know what to do with it which was even funnier.
Don't go for the super drunk girls - other girls will see that and rule you out as a creep. If there are only sorority girls... that kind of sucks. They're insanely cliquey and you may want to read a little bit about girl signals and how to copy them. But you can open small sets of them and ask their opinion on being in a frat - most of them will tell you they don't like frat guys. Then ask them "then what are you doing here?!" If you meet other GDIs (God-damn Independents) you can always talk about how weird frat parties are and build rapport.
On the dance floor, just be the biggest guy around. Don't walk up behind girls and grind on them with your hard-on, they don't like that. Just approach a group and start dancing and having fun. It doesn't even matter if you're a good dancer if you're having fun. Raise the roof, do the shopping cart, rock the Macarena on Lil Wayne songs! Don't drink too much and don't offer to walk wasted girls home just because you're a nice guy, they're such a hassle.
Hand girls your cell phone, they'll know what to do.
So, in summary:
- Say you're interested in Rushing the house
- Don't come with friends who will show Lower Value
- Give the guy that invited you props but don't hang on him either
- Dress the theme or dress like a champ
- Just have a blast and you should start seeing IOIs from tons of hot girls