I did hospitality for about 6 years, worked both as a waitress and in the kitchen. I have worked in clubs, pubs, hotels, restaurants and David Jone's restaurant (for a year and a half)
Tinka was spot on don't stand around doing nothing, try and look busy.
Try to wear your hair up, pulled back, if its long.
The chef is in charge of the kitchen, no matter what the manager says. Chef's can be VERY aggro so best not to upset them.
Make sure you know how it goes, ie I was ALWAYS taught that you don't take the plates until EVERYONE on the table has finished eating that course, it was the "golden rule". But I notice some places don't do it this way and it really drives me NUTS.
I wouldn't take it personally in regards to the manager at the club telling you there aren't many shifts. I would say that someones "family member" or "friend" has been slotted in there instead.
Lots of people think being a waitress is easy but it can be VERY hard work when its busy.
Good luck