Sponsorship is ALL about professionally REPRESENTING the companies' image, giving them 'BUSINESS NAME EXPOSURE', ( AFTER ALL, THAT IS ALL SPONSORSHIP IS, BUSINESS NAME EXPOSURE). You NEVER, NEVER, NEVER promise any monetary gain for you sponsor. However you CAN PROMISE 'BUSINESS NAME EXPOSURE' by assembling and following through with a conservative yet effective race and show schedule including appearances at your sponsors location as the race/show schedule permit. DO NOT promise way more than you can REALISTICALLY keep up with. ONLY promise via a mutual SIGNED contract what you can deliver and not any more just to 'sweeten the pot'. Better to be less than too much. Work in all possible scenarios including failed equipment(both race and tow), you and /or your crews health, etc. and a clause for natural disasters, etc.
Above all, keep in constant contact with ALL your sponsors no matter how small or large via an emailed or snail mailed 'race day update' news letter with good photos showing the sponsor's decals on your car. No matter WHERE you place on race day, show that you are ACTIVELY participating and giving it your all. Form up a fan club within your website to further 'expose' your sponsors' business names.
Work WITH your sponsors to 'give them their dollars worth'.
Find a local T-shirt shop that might sponsor team wearables in exchange for a spot on your car. If you aren't comfortable or just will not have the time, find a local website developer to work up your website in exchange for a spot. Etc,etc.
"Maximum utilization of available resources"
The larger the spot on your car/trailer/tow rig/motor home the more money it commands. The rear quarters(on a door car) usually command more than any place else.
Remember, there is a lot more to sponsorships than someone just forking over a handful of money to you. It is a BUSINESS PARTNERSHIP. Treat it as such. The Golden rule is prevalent !!!
Good Luck and have FUN with your sponsors !!