Citizens regularly change state and local laws via a combination of direct action, such as running for office, and indirect support for candidates and issues they support and by voting. The Federal Election Commission encourages people to get involved in politics by offering a citizens' guide to the various options open to them for influencing policy decisions.
Some opportunities for political action, such as voting, are fairly well-known and widespread methods that citizens use to influence the law. Others, such as donations to candidates' political campaigns, are bounded by complex laws governing who may donate and in what amount. These passive methods are sometimes effective in promoting candidates and causes.
More active measures listed on the FEC website call for more attention and dedication to changing the law, but they empower citizens to make the specific changes they support. These direct methods include volunteering time and effort to a candidate or cause or allowing property to be used by a campaign.
Citizens that live in a state that allows ballot initiatives can gather signatures in support of legislation they wish to see enacted. The California Secretary of State's website encourages people interested in this process to check with local election officials for details on their local initiative process.