This may have been discussed before, but my friend and I have used this effectively on many occasions.
If you're sitting at a bar that is full, people are always coming up to the bar to get drinks, and they typically go to the areas where there is a sufficient gap between two seated people. Creating such a gap between yourself and the friend next to you means girls are always coming to that area. All I ever have to do is give them a "hey how you doing?" and it almost always leads to a conversation of at least a few minutes. At that time you can decide if you wish to pursue it further by going for the number, etc. The only drawback is determining which of you will be talking to which girls, but fortunately I was hanging out with a married guy so he was just there for the fun .
If you're sitting at a bar that is full, people are always coming up to the bar to get drinks, and they typically go to the areas where there is a sufficient gap between two seated people. Creating such a gap between yourself and the friend next to you means girls are always coming to that area. All I ever have to do is give them a "hey how you doing?" and it almost always leads to a conversation of at least a few minutes. At that time you can decide if you wish to pursue it further by going for the number, etc. The only drawback is determining which of you will be talking to which girls, but fortunately I was hanging out with a married guy so he was just there for the fun .