Fight Hunger
Advocacy is nothing more than speaking up about issues you care about to people who have the power to make decisions.
It can mean asking for special help for your own child by speaking to a teacher or principal. It can mean asking to speak to a manager when the customer service person won’t give you a refund. It could also mean testifying at a city council meeting or even meeting with your Congressional representative about an upcoming vote.
The only requirements are that you learn a little about a problem that you care about.