Hire a photographer to take head shots of you. Doing so can cost from $75 to thousands of dollars. You don't need to spend a ton of money on head shots, though you want a sharp image that shows confidence. For Disney, you also will want to smile and show a lot of character. Have the photographer do touch-ups on your best shot. Print off 8x10-inch copies of the best image.
Attend acting lessons to acquire enough training to get the attention of agents and casting directors.
Write a resume that includes your height, weight, hair color and eye color. Add training and experience. You may need to act in a few independent films to be able to acquire an agent, though if they like your look, it shouldn't be too difficult.
Submit your head shot, resume and a quick cover letter to agents that you want to represent you. In your cover letter, mention your intent to become an actor on TV. Don't include that you want to act on the Disney Channel, because they likely will see that vision as too narrow. You want to be open to any auditions.
Continue to train and update your resume while you wait for a call from your agent. Tell your agent that you are especially interested in auditioning for Disney Channel for Kids. It will be OK to say that at this point.