That's easy, plain and simple, always treat the staff real good! TIP!!! ..even if it's just water you asked for. You'd be surprised how often the staff's approval of you is considered for a return engagement. Especially if you're an open mic'er looking for stage time. TIP!!
It works like magic! You should not be surprised to know that treating a venue's staff well and behaving professionally is a key to your image there. Remember, for the most part a staff doesn't get to know you, they see you barely when you arrive, they see only part of your show if they're busy,... so one of the big things they have to draw on is if you have a positive attitude towards them and you TIP!!!! ;) And btw, intro yourself around the venue, say your name to several people. Somebody will recall it at the right time when they talk about comics they liked vs didn't like. So TIP!!
Got it? Introduce urself to the staff, project a sympathetic attitude towards them. (Its not an easy job they do and a successful comedy night is not ENTIRELY about you! )
Then go stage and crush it!! Win the venue on and off the stage!!