One small step could be school uniforms or rather a specification for clothing. It seems to be legal in any school, public or private.

Longstanding has been the debate over the effectiveness of school uniforms.

Traditionally reserved for private parochial schools, school uniforms have recently been implemented into public high schools throughout the United States. Dress codes banning the wearing of revealing, suggestive, inappropriate, and/or gang insignia clothing have
been replaced by a more strict uniform policy allowing students to choose from an array of solid colored collared shirt, pleated pants, jumpers, sweaters, cardigans, and vests.

While many students oppose this adoption of a school uniform policy, critics argue, citing the longitudinal study completed by the Long Beach California Unified School District, that school uniforms foster a more academically focused learning environment, enhance school safety, heighten school pride, and reduce truancy, absences, and violent acts.

Following in the wake of the horrific school shooting at Columbine High School, the issue of mandating school uniforms in public schools has come to the forefront of educational debates. Since the massacre, schools, both public and private, have increased security and rewritten their dress codes in order to further restrict dress.

Despite these preventative measures and their correlated results, many pose the question if these actions are needed in their local schools. Research conducted by means of qualitative observation, surveys, interviews, and literature reviews examines and analyzes the need
for the implementation of school uniforms at PNHS

http://www.kzoo.edu/educ/sip/2004sips/Weitzel.pdf