1: Please double check that you are following the rules for the competition.
2: Feel free to ask for clarification on anything.
3: Don’t rush yourself, you will produce a better entry if you take your time.
4: Self check your entry prior to submitting. This will help cut down on the chances LUA errors.
5: Try not to release too much info about your car during the submission phase.
6: The most important: Have fun.
I always find #6 to be the most important one, if you’re not having fun and getting frustrated then STOP and quit the game, walk away from the PC and do something else for a time. Come back to it when you’re in a better mood otherwise this will taint your whole view of the game/challenge and may force you to not play it again.