Here's some ideas to get you started.
I asked questions because I love to do themed baskets. So if I was gearing towards summer I'd use a beachy tote with sunscreen, lip balm, insulated water bottle, and/or flip flops...maybe a beach towel. Not sure of your spending limit.
A hair themed one:
A canvasy basket with No pull hair ties like Teleties come in so many sizes and colors. Add some great smelling organic hair shampoo and conditioner.
Generally spa themed:
I realize you said she's not girlie but even the tomboyish girls seem to like the Treehut body scrubs as gifts. Many nice scents available at Target or Ulta. As matter of fact Target has large islands with general toiletries that aren't necessarily girlie but definitely good general use.
Home decor:
Cute, dry erase boards, photo boards. Also, Yankee candle or bath and body works has candles and scent room warmers
Craft themed:
If she crafts, then a plastic case with dividers and some new supplies. Many teens like to doodle so then watercolor pens and paper are nice.
If you know her phone, then a new case is always welcomed and a wristlet wallet.
Hope some of these ideas help!