Lately my go-to outfit has consisted of the American Apparel circle skirt, or any of their skirts, thigh highs/knee highs, and an oversized sweater, and shoes vary. When I wear these things together I automatically think "school uniform", I'm actually starting to take a liking to school uniforms because of this. But, I'm stuck in a public school. *sigh*
Now, plaid basically screams school girl so a plaid skirt might be overboard for you, so just try a solid colored skirt. As for shoes I chose these metal toe capped boots because you don't want a shoe that literally makes you look like you just came home from school. Both these skirts are from American Apparel and the thigh highs on the top, the bottom ones are from Urban.
Oh, by the way, some people have asked me to do a bun tutorial so I will be doing a tutorial for how to do a top-knot bun soon. You'll be surprised at how easy it is!