Fluttershy's Head

Well I'm certainly no expert in shading but since you're asking...
I think what's wrong is there's not enough variation between the midtones, highlights and shadows. And if you print it out (especially with CMYK ink) you can hardly tell there was any shading.

The positions are correct. Just concentrate on adding more contrast. And remember that if highlights use less saturation then shadows will use more, or vice versa.

Yay, it's my first critique on another picture Hope it helps