I'm assuming we're talking about DJ'ing the girls here nto just furthering your career. My advice for your first day would be rather than just hitting on the girls, get Alpha in everybodys eyes. Then you can start DJ'ing the girls later in the week. Being Alpha has the added advantage of furthering your career also.
1 - Assuming your conversation skills are up to scratch (re-read the conversation threads in the bible) spend at least five minutes talking to everyone, including the managers. Try and talk about stuff outside the store / job. Find out one interesting fact about everyone. Bail elegantly if the conversation stalls or you'll look bad.
2 - Get comfortable in your environment as soon as possible. Have a good nosey about if you get chance, find all the little cupboards and back rooms and look out for useful items that might be neeed. Knowing where everything is, and more importantly where you are is a key part of projecting Alpha traits.
3 - Be ****y and funny, but don't diss the managers. Be a leader from the start, if you have a two man job to do like shifting a sofa or something, find someone at a lose end and TELL them "hey [name] come and give me a hand with this will ya?" then chat with them about some light topic, and thank them for their help. Nice guys ask, leaders lead. But don't tread on any managers toes.
4 - Find the quiet ones and build them up by talking to them and getting them to talk about themselves particularly when the group is together. Validate their opinions even if the rest of the group is rejecting them. If they are obviously copmpletely wrong and you can't find anything valid in their opnion, try and correct their mistake by showing that where they went wrong was a mistake that anyone could have made.
5 - Find the confident ones and mirror them until you get up to the point where they start mirroring you. Then make sure you always have them following your lead.
6 - Use Kino, even on the blokes, even on the Managers, obviously I don't mean stroking arms suggestively (unless you're actively trying to DJ a girl at that point) but a pat on the back or a guiding hand on the shoulder, even a firm handshake are all key ingredients to the Kino technique.
If there are groups already formed there will probably be two types. The ambitious "suck up" type, and the laid back "minimum effort" group. Groups that have formed in a work environment are often best left as they are, but you need to establish yourself as a member of all of them. You should feel just as at home hanging with the laid back group as with the work minded group as with the managers.
Now some of these techniques will get you well in with managers and should help you progress if you decide to make a career with this company, but most importantly from a pick up point of view they will get you noticed by the ladies.
Be careful not to find yourself in the "friends" zone though. At work there is often a "sub friends zone" I think of as the "colleague" zone - as in "Oh I could never have a thing with someone at work, it would be too wierd if we broke up."
You get into that zone by staying out of the friend zone but having too close a working relationship in the work zone. You'll also become undateable if a girl thinks you can't be discreet.