Get experience and acquire some skills. The Disney channel is a international media brand. Have your daughter try acting in a local kids' theater or in more accessible local productions to get some experience and a taste of acting. Learning some skills such as singing, dance or stage fighting will come in handy and look good on a resume.
Prepare a reel and package. Having some professional head shots and a demo reel are vital for attracting interest.
Watch shows on the Disney channel and look for the production companies behind the shows. Disney does not produce all the content on their channels alone. Make a list of the production companies associated with the shows. Send out a letter of inquiry along with the head shots and demo reel to these production companies.
Approach a talent agent who works with child actors. Send the agent the girl's head shot and demo reel and, if possible, have your daughter meet the agent. An agent will help the girl find work by using an existing network of contacts.
Go to some Disney channel show tapings. By actually being on set, your daughter may have a chance to meet the producers of the show. If they like her, they may cast her.