Join the drama club at school. Audition for community theater productions. Local agents go to school and amateur shows all the time, scouting for talent. If you don't get cast immediately, offer to help with props or costumes. Get into the arts community in your city and get to know the folks who can help you move forward. If there are casting agents in your town, call them and ask what you need to do to get film and commercial work. A qualified agent will ask for head shots and a resume, but they should not charge you any fees until they get you a job; then they take a percentage.
Go for it!
