NHRA Welding rules??

First of all, don't practice on your project. Use scrap metal. Make sure all pieces are very clean. Weld all different types of joints, at all sorts of angles. Check out some welding forums like Miller welds or other non-sponsored ones, and you can ask general questions there. Treat every weld like its gonna be the best weld you will ever lay down. Don't think "nobody will see it, so it doesn't matter".

I tech cars at my local track, and we don't ofter check frame connector welds and such, unless it is a quick car, or maybe if there is a roll cage and it's tied into the connectors (recommended).

The best advice I can give you though is don't be afraid to ask a pro for help or lessons, it's ok if you're not good at it, it is better to admit now rather than hurt yourself later.