Today I went downtown with two of my friends and one of them decided to call up some girls. When they finally arrived I noticed most of them were 8.5s or 9s. I said hello and all that but it was still awkward since my friends just kept talking to them but since I didn't know them I was kind of left out of the conversation. I was was mostly silent but when I did talk these girls either ignored me or just replied quickly and then went back to talking with my friends. After about an hour I could see this was getting bad and just decided to leave.

What could I have done differently to build more rapport with these chicks?

P.S. I'm not ugly and most people say I'm a good looking guy so obviously it wasn't my looks that turned them off.

Damn. Why didn't your friend introduce you? I hope he wasn't AMOGing you.
Well what you could have done is introduce yourself and ask their names. Then make the conversation more interesting by asking "How is it, that such beautiful girls are friends, how do guys know eachother?". Then talk, talk, talk. When they start asking you questions, you know you got em. Just be warm and friendly.

Why are you out of place?
why did your friends didn't introduce you? Are tehy insane?
If they can't do that part just do it by yourself.

Good job putting up with them for so long. Major Kudos to you for that. That being said, the fact is very simply, boy. If you want to build rapport, BUILD RAPPORT. Ask questions, be involved, TALK. Don't just talk, SPEAK UP. If you have something to say, say it loud and BOLDLY. You probably felt a bit out of place and must've mumbled. If you didn't, I apologize. There really is no shame in admitting that you did though. We all went through that phase. Keep putting yourself in these situations until you get comfortable with them and watch the rapport develop. It gets way easier over time.