If you are invited to a studio shoot, this means that most of the things like models and theme are very much out of your control unless they ask you for suggestions.
A few guidelines, other than the ones mentioned above
(1) Don't hog your time slot for shooting, especially if you are shooting in a group. If you are given 3 minutes per angle, try to keep within that three minutes
(2) Most DSLRs can produce good results, not to be worried, even if the camera is an entry level camera. Good to know what you are shooting so you can prepare your lenses, or go rent one
(3) Pls don't change the lighting direction set by your friend during your turn of shooting, as others also need to shoot
(4) You may like to ask your friend if they are using wireless transmitter or cables, and whether you camera can use the cable
(5) Be courteous to the model
(6) Enjoy yourself
Cheers
Steven Yee