Well here are some other things that help:
1. Race
b. Practice
2. Race
c. Practice
3. Race
d. Practice
4. Race and keep results, compile a race resume
5. Obviously as is covered on underground, be nice, be someone that they would want to sponsor, be helpful here and on the track
6. Browse the websites, some have links for sponsorship details, I know Byron had a really good program that paid out for races, check them out.