I want to get better at cold approaching at bars/clubs, but I find it really hard. I have no trouble walking into a house party like a boss introducing myself to everyone (it helps being a DJ, but anyway), but at clubs/bars I just don't know what to say.

If a girl opens on me or compliments my shirt or something (I peacock sometimes), I have no problem. But what are some tips / general good openers, or strategies?