Lasiorhinus is spot on! Definately file a flight plan and call the Perth ATC the day before to get an idea of what times will be the busiest.
Last time I flew in there we only filed the flight plan prior to departure out of Jandakot and ended up holding at Mullaloo point for about 15 minutes.
If you haven't done it before, make sure you have a good chart of the terminal area (the one out of DAPS is probably best). Be ready to receive and read back lengthy taxi instructions. If they offer taxi guidance... take it. Saves you looking like a mug if you take a wrong taxiway and end up your nose to nose wheel with a 737 or something bigger.
All in all, it's good fun and experience but I would also heed bentleg's advice and stongly advise having someone on board who has done it before.