You were trying to hard. Should have acted unavailable, UNATTAINABLE , meaning these girls would have no shot with you. The idea of moving around the party and speaking with other people is not a bad idea, this shows that you are not just speaking with these two other girls, but have other options.
However, next time try to have people gravitate around YOU rather than you around them.
If you were getting some serious eye contacts with this woman, you should have came straight up to her and say something along the lines of:"You need to stop doing that, i'm not that type of guy" then just walk away.
This comes off as cocky, mysterious but also marks a point that hey, if she wants you, shes going to have to try way harder.
I used to have the same problem but now what I usually do when around a beautiful woman is tell myself that I am the PRIZE and that she NEEDS me. I don't need anyone or anything because I can get everything I want when I want.
Tell yourself that she isn't even that hot, or try finding things you dislike about her. But watch out, don't get turned down!
Even if this is not particularly true, it helps you boost your confidence and puts you in a situation where you feel desired. Thus relaxing yourself, feeling better around woman.
The women will not only feel that you are in charge but it will attract them!
Another thing that I practice is ataraxia. If you've seen the movie Slevin you should understand what I mean.
Josh Harnett has a "disease" in which nothing affects him emotionally. He gets mug, reacts calmly, the guy NEVER gets tense. Women LOVE men that are always in CONTROL and that are not affected about what is going on.
This is similar to Hank Moody in Californication, he can be in a horrible situation, just got his car stollen or whatever and he'll be like "ah crap whatever".
I've practiced using this technique and its always been positive for me.
Hope this helps
