I did Gloucester on my QXC and it did seem big and scary the first time (that changes with experience!)
As said, get the ATIS early if you can (do you have two radios? if so use box 2, if not you'll have to get it between your old frequency and the Gloucester Approach one). Also look at the wind before you leave your home base so you have a good idea which runway or runways to expect (but don't get stuck in that mindset and ignore what the ATIS actually says!)
Otherwise, if they want overhead joins then make sure you are confident. The easiest way I have found is to approach the airfield at 2000ft AGL keeping it on the same side as the circuit direction (e.g. if it's LH, then on your left) and fly a circle round in the overhead until you are over the numbers of the runway you want. That puts you in position for a deadside descent without having to do any more turns.
Tim