Thai university uniforms should be the guide Thai universities have awesome uniforms and I think we should adapt outs from them. What I would do is as follows:
The girls should be required to wear white short sleeved, button-down shirts, sleeves down to mid-bicep, with square hems, and black or navy skirts. The skirts should be short--no shorter then 3 inches below the panty line, no longer than mid-thigh. Open toed black shoes. Tights optional but transparent. Of course these uniforms are very sexy looking and most girls would like them a lot, but religious girls and girls who are embarassed to show their legs should have a more modest alternative.
Boys should wear white, button-down shirts that are fitted and with long sleeves. Ties are anachronistic and shouldn't be required. The shirt tails should be tucked in at all times. The pants should be black or navy and of a tighter, 'skinny' fit. Black dress shoes. Boys who are overweight or otherwise can't physically wear this form-fitting uniform should have a looser alternative.