This outfit was made by my sister Emma. The galaxy trend has been going strong lately. A lot of outfits that I have seen use galaxy print leggings in the outfit, but if you aren't quite that bold, you can wear a shirt with some jeans for a very casual and wearable outfit. But if you want to go for the legging look, I would wear a solid top in a corresponding color (or a neutral, like black). I would also suggest that the top be long enough to cover your rear, since leggings tend to cling. Or you could wear a simply shaped, neutral colored skirt over the leggings, for slightly less impact and another cool look.
As for shoes, you can basically wear anything you want! Leggings would look good with TOMS or Converse for school (or just anytime!), sandals in the summer (although why would you want to wear leggings in the summer?), and boots in the winter.
And lastly, have fun with the accessories!:)