I remember when I was in high school I was always bucking the dress code, which was strictly enforced then. I got sent home a few times for having my skirts too short (1 1/2 inches above the knee was the rule). My mom would always make sure when she made my clothes that they were the "proper" length. As soon as she would leave for work the next morning, I would hem them before I went to school. On one trip to the dean's office I remember her trying to explain to me how it distracted the boys so they couldn't keep their minds on their work. Of course, that was also at a time when the schools still thought education was their job.
When my daughter was a teenager, there was a slightly different problem. Most of the girls in high school either dressed like tramps or slobs. My daughter was very fashion conscious but she never seemed to quite grasp that there is a fine line between tastefully attractive and too revealing. Fortunately, she tended most of the time to do alright, but there was always that compulsory rebellion factor to deal with.
I think in the context of today's lack of morality it is very difficult to teach girls about the messages they send in their manner of dress, but that makes it all the more important to make the effort.
"I remember when I was in high school I was always bucking the dress code"
Bless you my child, bless you.