I don't know if it was Plowboy (forgive me if I am wrong), but when I was doing research for my first comp someone posted about the work boxes. When you practice, work out of your boxes. If you have to go to the kitchen for something make sure you write it down so you know to add it to the box. That will let you know you have everything. As Mista's thread said, after the first couple comps you will start to really cut back on what you take with you. The less you take, the less stress there is at set up and tear down time.
After you get home from each comp, go thru your boxes as you clean up and make a note about what you need to replace before next time. We do about one comp every two months. That gives plenty of time to make little purchases and eases the pain of the price to compete for a low budget team like us.
One huge mistake we made at the last comp of the year for us, I tried to cook extra meat for a church picnic the next day. 14 extra butts. I thought I had the time down for it to be done before rib time, but it was way too close and way too much stress. We do take orders from friends, co-workers and family and cook that meat for them on Friday or just take it out of extra butts after turn in times. It helps some of the guys on my team afford to come play.
Big Blue BBQ
Weber one touch gold (blue of course!)
Jack's old south cooker