First, I'd highly recommend getting a packet together to present to any potential sponsors. (Jessica Boucher put together a nice paper on the subject that I'm too tired to find--it's in the White Papers section of the site.) If you've got someone that can get a decent-looking brochure/booklet/napkin sketch together, you'll be good.
Second, no donation is too small. (1293's sponsorship goes as low as $10. Granted, we don't recognize it as much as a $1,000 sponsorship, but it helps. $10 is halfway to a day with a U-Haul to get carts and toolboxes and such to a competition.)
Thirdly, be creative in looking for sponsors. They don't necessarily have to be machine shops or big manufacturing companies--teams have been sponsored by everyone from proctologists to Busch Gardens. Very few industries are ill-suited (and I'll leave you to guess which ones those are).
Finally, look through the Fundraising forum and white papers. Few ideas are too crazy. Teams have held LAN parties, have duct taped teachers to walls, had bake sales, washed cars, and done a million other things to raise money. We're glad to offer advice and tips on how to make things more effective/saner/interesting.
