Just practice, practice, practice and when you think your good enough practice a little more. Have some other people look at the practice welds. Weld some tubing and then cut it apart to see how well you penitrated. Do some reading about the different processes for different types of metal and applications. I welded my first suspension and chassiss, but had been welding for many years before hand.
SAFETY is the biggest issue I have with guys welding up a car that have never really welded. It's not just their lives and equipment at stake. It's also the the other competitors and spectators that are at risk.
Just my $.02 good luck.
