i basically DHV as much as possible and flip dynamic.
conditions are also a big factor. like slow days or late nights etc
youre gonna hear a lot of people say "you dont become a girls friend you want to bang" etc but within this context (and a few others) i tend to build rapport by being a familiar comforting face. for bar tenders for example i'll show up with a date or flirt with other girls on her busy nights. and then switch it up on slow nights. ill show up and treat it like a date. ill play the role of a bartender and hear her out. you know, treat her like a living human being. banter, humor, kino good convo etc etc. you should be able to judge her interest through her interaction with you and will know when the right time comes to ask her to hang out one night after her shift.