well, in my case, when i got sponsored by kicker.... i had to spend boatloads of money on my setups to be competitive, i competed for a few years, earned a good reputation, won tons of shows, was always fair with other competitors whether i won or lost, and showed that i was willing to travel all over to do big shows where the products could be seen.
you gonna have to spend lots of money, do lots of show, and show the manufacturers that its worth it for them to invest in you.