Well, first of all, it doesn't look like you're using your layers, or at least you've put your color layer over your lineart layer, which can be a pain too. XP If you want to scan some lineart, then color it on photoshop, the best thing to do is take this thing called the magic eraser on your tool bar and click it over the white spaces. It'll disappear instantly because it erases large plots of pixels that are all the same color. Then You can go in and create a color layer, for base, shading, highlighting or whatever behind the lineart layer.
Maybe you already knew that, but if not, hopefully that'll help. I'm usually bad at trying to help unless I can be there and see what you're doing.
And in the words of Mr. Bo - "More values!"
Also once you get everything else together, maybe try adding a soft, 'transparent' color, a complimentary maybe or something close, to give the background a little more depth.
All this critique is said with love!

--
"It's dangerous business, Frodo, going out your front door. You step onto the road, and if you don't keep your feet, there's no knowing where you might be swept off to."
-Bilbo Baggins The Fellowship of the Ring

I'm always open to constructive criticism.

I thank you greatly for it
I kept trying to remember what I would do in class but EVERYTHING left me! I was like "Uhmm..layers, I remember that..." and that's about as far as I got. I tried to shade as best as I could. Started over 3 times but I just couldn't remember how to do it anymore! Like, with the shape of her head and stuff. It was a disaster.

--
"For future reference, Harry, it is raspberry...although of course, if I were a Death Eater, I would have been sure to research my own jam preferences before impersonating myself."
-Albus Dumbledore

Just try to define a light source first. The first thing about shading is that you have to keep in mind what direction your light is coming from so it doesn't look all wonky. But I know what you mean, I've started pictures over several times all because my shading is wrong!

--
"It's dangerous business, Frodo, going out your front door. You step onto the road, and if you don't keep your feet, there's no knowing where you might be swept off to."
-Bilbo Baggins The Fellowship of the Ring

I'm always open to constructive criticism.

Yeah, guess I'm having trouble with that lately. Ugh. So out of practice @_@

--
"For future reference, Harry, it is raspberry...although of course, if I were a Death Eater, I would have been sure to research my own jam preferences before impersonating myself."
-Albus Dumbledore