"he knew what he was doing"
Girls always know what you're doing, even before you know what you're doing. Especially the hot ones. They've seen it hundreds of times before.
in fact i kind of ignored her
So, in fact, you did behave differently with her. She will have noticed this too, and will have taken it either as shyness, or game-playing. Probably the latter, by the sounds of it.
I went over the the one girl and she completely avoided looking at any part of me.
She also knew what she was doing herself. She was playing the game too, and probably did like you some, but wasn't going to give you the benefit of checking out your body. She'd be just like all the rest if she did. Maybe she was a bit nervous as well.
It was a pool party thing so of course the shirt comes off and the women look.
Of course it was a pool party, so you get semi-naked. However, the fact you mention it means you are/were focused on your own physique; nothing wrong with being proud of your hard work and showing it off. This self-admiration will likely be communicated through your body language, especially the way you carry yourself, which might be interpreted as egotistical by some - "
he knew what he was doing....".
I went around and introduced myself to all of the strangers confidently and friendly.
Again, confidence and friendliness, you're doing everything right. A bit like the last point though, there is a fine line between confident and friendly vs. over-familiar.
So, two last points, in light of the above and with view to closing the chick next time...
-With over-familiarity in mind, we don't always need to go around introducing ourselves to everyone at once, rather just allow it to happen naturally through the course of a night, even if you don't end up meeting everyone. You might look a bit like a people-pleaser, or worse still, attention-seeker.
-In the same context, keeping the goodies under wraps (even for a while) can serve just as well, if not better than a rippling gun show. A tightly-fitted t-shirt achieves the same ends, while maintaining a little bit of mystery. Or, next time out, flirt with a girl so much that she
tells you to take your shirt off, better still, takes it off for you.
This mystery and process-for-process-sake is the biggest part of seduction for women. They love the dance and you can ration her to tasty morsels to begin with, just enough to keep her hooked; she'll be yours for the taking, probably by the close of play. Ripping your shirt off and running round the place talking to everyone will get you attention for sure, but think about impressions as well.
You essentially did nothing wrong, though it may have been a bit obvious that you were on the prowl; in the wild, nine times out of ten, the prey doesn't know the predator is there until it's far too late. Maybe just turn the enthusiasm down from 11 to 9 on occasion. With hotter women, I've noticed under-gaming is preferred to over-gaming. We use the same hammer for every job, but apply different force depending on the size of the nail.