Classes help out a great deal in this. There's a good amount of them locally available. Other than that, put in only what you feel you cooked the best. If pulled is your best, put it in. It slices are your best, put them in. Check out bbqcritic.com for what real competitiors feel is presentable or doesn't appeal. If you put in chunks, slices, and pulled and two are stellar and one is so so, you will get judged on the so so. Take your time when turning in and practice boxes. Cut out styrofoam and play around with ideas. Sketch it in Google 3-D. You have to be able to think on the fly when it comes to turn in times. If you pulled out your rested meat and it's over-done but you planned on slices and chunks, know how to present pulled pork.
Backwoods Extended Party / Backwoods Party / FEC100 / Memphis Advantage / "The Hulk" UDS