Practice your recipe over and over until you have it down pat. Time yourself to make sure your dish can be done within the time limits.
Figure out options on each of your steps for if something goes wrong cause it almost always does and it's nice to have a backup plan ready.
Be calm when you're cooking and be organised. Clean up as you cook so you won't have to clean up to do something else.
If you're packing in your own ingredients, then double, triple, quadruple check your coolers and stuff. Carry your own stuff in if you can. If you can't, then keep a veeery close watch on whoever carries your stuff in for you. Once your stuff it at your space, don't wander away from your cooking area unless you absolutely have to.
If you have to submit an ingredient request, then make sure you're asking for everything you need. Even if it's part of the cooking process that doesn't end up in the final dish.
Have fun, but not too much fun. You're there to compete.
If the chefs give constructive criticism, then listen to them carefully. Their advice is gold and it will help you in future competitions (or even in your immediate skills).
Everything on your final plate needs to be edible. If there's a prop involved you can't eat then don't use it.
Remember that even if you don't win, you will gain experiences that will help your cooking skills tremendiously so in that way, you've won already just by being there and competing.
And the most important of all: good luck.