I've worked as a waiter before and the good thing with such a job is that you can politely Kino escalate without the girl even noticing you're doing so.
What I find interesting with this technique is that you can do this multiple times with multiple girls during the same night, which gives you options. Before you know it, people will be talking about that nice and polite waiter which, I think, is a very good dhv and very commonly it will be done by her friends without you having to do much - thus her friends approving you at the same time, and I find this really important!
What I do when I work as a waiter is softly touching and fondle girls while passing through saying something like "excuse me". Most commonly she'll be surprised by a stranger touching her, but as soon as she notices it's just a waiter who is trying to avoid any accidents, she changes her moods. The important thing here is, that when she turns around you make eye contact and smile at the same time. I have never received a bad comment doing so.
Also, because you are working there and she is having fun with her friends, most probably you'll have to repeat this again and again during the night. As soon as she gets used to you politely pushing her, she will no longer be surprised but flirting. This delivers an under-the-table-message: you are used to interaction with HBs, you feel very comfortable and you are not needy at all.
And then you can engage yourself in a conversation with her. You should start by just saying something simple and spontaneous and then LEAVE because, as mentioned above, you are WORKING there. And then come back again and continue your conversation. At this time, you should keep your sentences short and spend little time with her.
Before she (or you the very first time) even noticing, you will be having a conversation in chapters going.
After that, it is very simple to Isolate her and step up to the next level. You could then say something like "I've never seen you here before - is this your first time?". The thing is, it doesn't really matter what you say as long as you're keeping the partying mood going.
Eventually you can #-close, k-close, arrange to meet her after your shift or leave the place with her, invite her to some event on another date.
Either way, it is a win-win situation! You will be having fun while making some money and even if you close no girl some night, people will remember YOU and the fun they had at the place which will be bringing people back again.
However, you should be very careful not to cross that thin line between being funny/cocky and rude. If used right, it is guaranteed to bring you good results.