Our first and only comp was last year and I would say my list would be:
1) Water bucket of some sort (we forgot them)
2) Pre-prep/trimming of food
3) Ice can be expensive on site
4) We had a few 2-day practice runs with turn in boxes leading up to the event
that helped a ton!
5) Don't be scared that your doing something wrong. Everyone has there own
way and no one will think your stupid for lighting your pit at a different time
or putting your meat on an hour later than you neighbor.
We had a blast and got a call in chicken which we thought was pretty cool!! We did well at our first event last year and Donkey Punch BBQ will be doing 4-5 more this year, just not sure where yet :)