this may sound very basic but you can never have enough duct tape and electrical tape. Duct tape if anything can be used to hold carpet together for practice. Electrical tape will be used a lot for batteries and such. A box cutter is always a good idea to have around. Also keep a small first-aid kit (latex free if someone is allergic) and a fire-extinguisher around not only for your safety, but also for safety judges at competition. Sharpies and dry-erase markers are useful to mark basic lines on metal ( I have even used liquid white-out), though you dont want to use them if you need really precise cuts. Allen wrenches (both L and T handle) are both useful. Pencil and Paper to make hardware store- run lists. Once you find out the challenge you will probably want to build a mock field to practice on, which can often be made out of wood, so you could possibly talk to a local lumber yard about donating that

. Most importantly dont be afraid to ask for help. This site is my best-friend during build season. Good luck and I hope you have a great season