Get a job at a shop and network thats how i get hooked up with smith and salomon a few years ago. i also just got a free pair of dalbello rampages for free to test out. Its all who you know and what you're willing to do for them. but read my qoute below too. good things happen to good people.
shred the gnar and mean it. who cares if you get sponsored, if your skiing for the free shit then your not really part of skiing you ski to ski not to get free shit. but if it does happen to work out, take it but dont be just ride for sponsorships. ride for you.
i just went to my local shop and showed em our edits, got the whole crew sponsored, they only pay for comp fees, but when your still in highschool, i dont think you want to deal with much more than that
when i got sponsored forward left 7 ws my best trick. just go to comps and give off the immpression that you are going to be on the scene whether you get hooked or not. then even if you dont youll have a good time on the scene.