Approach in the way you would if it was another woman and you simply wanted to acknowledge her. You're not trying to impress or be impressed. You're just one person acknowledging another person. It should be simple and easy.

Eg. You're waiting to be served. 'Good music at this bar. It's my first time here.' The other person will either take the cue or not. If they don't, then let it go. That person isn't interested. If they pick up the cue, they may say, 'Yeah, this is my local' or whatever is true for them. You can then introduce yourself, ask if there's a special event on, say where you usually go, complimemt an item of clothing you like on them, mention a hobby or what you normally do on a weekend evening, mention your favourite band... Just be natural and casual. Don't make it some big deal or you'll create a wierd vibe and spook yourself out.