Start with a purple flowered, button-up top...
Add gray dress pants and my favorite purple flats!!! I especially love that when you walk they sound like heels, but they're really not.
Next make your hair wavy by sleeping in French braids (one of my favorite hairstyles. I shower at night, then French braid my hair right after. Go to sleep. Wake up the next morning and take out the braids. Voila!) Add a lavendar headband/tie thingy. (one of my students complimented me on my headband, I thanked her and told her that it is really a belt from a top I bought, but I didn't like it as a belt, so I use it in my hair :)
Accessorize with simple silver jewlery- big silver hoops and my Irish knot ring, complete with purple stone.
And tada! You have a fabulous, school appropriate ensemble!
Sorry the picture kind of sucks, I thought I got a better one...