Here are a few tips...
Standing in the bar, try to throw random comments to people around you, and don't even expect an answer. You can start with compliments. If you don't look like you expect an answer, the compliment will seem honest and people will most likely respond positively. This way you are not intrusive, and should make you feel comfortable enough.
If you are holding a drink (I suppose you drink something, even if it is non-alcoholic), you can toast with people who are passing by (or who you walk by, if you are the one walking). Just let them continue wherever they were going, or keep walking yourself wherever you were heading - not expecting any response, not being intrusive.
In general, you have AA because you know that you may be intruding someone's personal sphere. I don't think approaching as in walk-up-to-someone-and-initiate-a-conversation is any good unless you have made eye contact with the girl already, and she was smiling to you. Avoid that. But you can approach this way if everything about you communicates that you want to give value rather than take it.
Here is a very unusual tip in this community... If you are a camera nerd like me you could try street photography. It is a niche in photography that has much in common with daygame, approaching and making people feel comfortable in your presence.
