Take an informal survey among parents and students in your school to gauge their feelings about uniform policy and decide whether you have enough support to move forward.
Circulate a petition among parents and students, asking supporters to provide their names, contact information and statements supporting a "no uniform" policy.
Research the history of mandatory uniforms in your school district to learn about the rationale used for enforcing a uniform policy. This will give you valuable information to use in disputing the practice.
Find information on other schools in your area that have gone from mandatory uniforms to a casual dress-code policy. Talk to the administrators and parents and ask them what triggered the change, and how they went about implementing a new dress code.
Prepare a presentation for the school board on the benefits of revoking the school's uniform policy. Use performance statistics from other schools in your state to demonstrate whether there actually is a correlation between uniform policy and student performance.
Make the argument that uniform policy eliminates personal choice and freedom of expression among students, uniforms can place an unnecessary financial burden on families and forcing a dress code might actually make it harder to identify strangers or troublemakers on campus.