Here's how. First make sure, if you're of legal age, you're registered to vote. This is an election year. The voters will pick sherrif's & mayors & congressmen and senators & goveners. Find a list of candidates in your area. Contact them all and ask their views on marijuana de-crim (legal personal-use gardens). Campaign and vote for the candidate that is most pro-pot. If you want to be more active, you can contact city/county officials to find out the process to put a measure on the ballot. Signatures will need to be collected. Contact normal.com and they will put you in touch with local chapters that would be happy to have another volunteer on board. You DO count, especially on the local level.
In the state of Nevada, there is a current initative on the ballot to allow possession of under an ounce if you are over 21, and it is going to be on the ballot this november. Trouble is, not many know about it... Get out there and vote!
Trouble also is, even if it passes, which would be awesome, Federal laws would still be in place. So the cops would no longer be enforcing state laws, but federal still trumps
But the feds don't have the resources to stop entire states from allowing possession. If the states begin to legalize, the feds will have to back off eventually.