If you have to ask online about getting a sponsor, chances are you probably won't get one.
If you do think you're good enough to REPRESENT A COMPANY (yes, that what sponsorship is, not just getting free gear), then call up your local representative, tell him how many competitions you've won, and get him to watch you ride or send him a video.
'Oh, and Morocco offered 2000 monkeys to help detonate landmines (an offer which was refused).' - J.D._May