Get set up with an agent/manager.There, you'll get hooked up with small stuff, if your lucky, and maybe get auditions. Be careful, you wont get it on the frist try and might be faced with some rejection. Acting is a tough job, especially when your young. Let your parents look over any papers, READ CONTRACTS CAREFULLY, and trust them. Your parents, and hopefully your manager, will have your best interests at heart. Pick jobs carefully, some commercials, ect., might not be what your looking for.
The best way to become an actor is by first gathering information on what the casting directors require, this can be done by checking out industry papers and websites. Secondly, you can try out productions at your community theatre to polish up your craft. Thirdly, look for an agent who will be able to connect you with the acting job opportunities out there.
Commit. If you're in junior high, start audition for each school play until you graduate. If your school offers a drama class, ask your school counselor if you could take the class. Audition for community theater plays. If your local community theater offers a conservatory(classes at the theater) take acting classes there. If there is more there is more than one community theater near you, audition for plays every single one and take acting classes at all them that offer conservatory classes that you can depending on your time schedule. Audition every chance you get. Audition! Audition! Audition! When you get into high school, continue auditioning for school plays until you graduate high school. Never stop acting in community theater. If your high school offers drama classes when you get into high school, take as many of them as you can until you graduate high school. Go to college and major in acting. I recommend at least a master's degree. Read lots of books on acting regularly. A good book to read is "Audition" by Michael Shurtleff. When you are ready to become an actor, you will need to hire an agent. In order to be in any movies, you will need Screen Actor's Guild(SAG) card. However, you must be in a movie to get your SAG. That makes it difficult. By law, you can audition for movies for up to 30 days without a SAG card. At the auditions, you will be ask for headshot and resume or you will be asked to complete an audition form. You should always prepare a headshot and resume in case they ask for one. Acting in movies is a little different than acting on stage. Here are some tips: Never look straight into the camera. Imagine what you would look like on screen. Here are some stage tips: Don't be your character. Be yourself playing your part. Never turn your back on the audience. Project your voice. Don't yell.