You have to start by taking some acting lessons. You can put this on your resume. Then you need to join an agency so that they can find you more auditions. It would also help if you could put extra things on your resume. Like if you take choir at school, or any other talents that you have, or languages you can speak. It would help if you had small roles in student films on your resume, so that you have some experience prior to the role that you're trying out for. Hope this helps!!!