It can be done I'll tell ya that ha. It depends, you mean just in general, like a cashier or a waitress? Or a certain girl you've seen somewhere on more than one occasion?
Well If it's just spur of the moment, any cute girl working, it would be easy enough just to make small talk/ a joke, then be direct and say something like hey you seem cool I'm going to *such and such* you wanna go? or just ask her out, get number, somethin like that.
Waitresses can be more complex but if your with some peops and she starts hangin out with your group, maybe takin shots watever, then you can kinda just escalate from there.
If it's a girl you see somewhere often, just play it cool for awhile, wait for her to ioi, then find a common ground, maybe plan things down the road.
Hope that helps!
Good gamins 