How can I change a State law in America?

In MOST states, you can't directly vote on laws. You have to convince the legislature in your state to change the laws. In states where citizens can directly vote on laws, the first step is to draft a petition to place the issue on the ballot. The actual language of the petition must be approved by the ballot commission or equivalent authority. Contacting the Board of Elections will get you basic information, but contacting a attorney will probably be needed to draft the law so it actually does what you want it to do.

You have to first contact your local state representatives to find out if that is something they would sponsor.

Start by writing a letter to your state representative suggesting a law to "legalize drugs." Before you ask, you'll have to do some good old fashioned research to find out who your state representative is.

Drugs is illegal for a good reason! Lets keep it that way bud!

You shouldn't do drugs.

But if you insist on doing drugs, you shouldn't give a fvck what the law says. Just do them, and don't get caught.

If your state has the initiative process, you can gather the necessary signatures (usually in the 100s of thousands, for a big state, like California). If you get enough, it goes on the ballot, and you vote "Yes".

Get elected and don't sell out your principles.