Dance to the Music of the Galaxy

<img src="e.deviantart.net/emoticons/b/b…" width="15" height="15" alt="" title=" (Big Grin)"/> This looks amazing for a warm-up sketch!
I'm just going to critique this as I would an actual piece, so.
First of all, this looks incredible! I love how the character looks, and I love the color scheme you used. The anatomy is great, and overall it looks pretty awesome. I realize this IS a sketch, but I feel that the lines are too lite along some of the darker parts, such as her hair. A good way to fix this is to lock transparency on the layer and color over the sketch with a darker color at darker parts. Also, the shading looks a bit rushed on the shirt, but not too noticeable. The stars and the glowing orbs beneath her are very flat, but this works in this case, as it draws the view to the focal point, the girl. Maybe the orbs could use SOME shading, but I like it how it is. Overall, this looks really incredible- good work!!