A proper school uniform, at least.
It always slightly irritates me when, even the likes of Amazing Anna purport to be in a "school girl uniform" and then present in some ultra mini tartan skirt and cut off shirt and suspenders with knickers showing. As sexy as this may be intrinsically, it is NOT representative of a school uniform.
I saw a girl from Ashton, Preston many, many moons ago pulled from the Lancashire Evening Post probably (I think I reported on her under an old user name on Punternet possibly) Anyway I forget her age but late teens/early twenties and offering "school girl uniform". When I got there, whilst she looked ok, the "uniform" would have got her suspended from bloody St Trinians. I think I politely questioned her sartorial inspiration for this attempt and she said she had had similar criticism but that she couldn't find anything more authentic.
"Go to a school uniform shop", said I..."where your own mother went to buy your uniform. Thousands of kids are successfully kitted out more convincingly for the start of term each year".
"Oh yeah", came the reply.
I never returned so do know if my suggestions were heeded.