I hate linearting so much, I've actually developed a way to make a sprite without drawing a single line.
It's a bit hard to explain, so here, I took down the process to accompany the explanation instead :
http://puu.sh/1LAku
Basically I paint the whole sprite without lining it, on a single layer. Once I'm done, I merge everything. From the layers' options, I choose 'blending option' --> 'stroke' and then whichever line thickness is suitable.
This gives off the effect at picture 5 with all the flying black bits. The black mess is actually the leftovers from my painting from all the incomplete erasing. Then I simply erase all the leftovers and the jaggy edges until I get a smooth black line.
Once I get the line, I just duplicate the whole drawing's layer, color in the parts with whichever color I want, and use the overlay/multiply layer options until I get the effect I want. In this case, I had a layer set to multiply and one to color dodge. Of course, you can still use this lining method even when you paint with colors, but this is even faster.
The final product would look like this:
The down side is that you may have lesser control over your colors. As you can see the face is darker than the rest of her skin but that's nothing you can't solve with a bit of color balance and extra painting.
Overall, I finished the whole sprite in an hour, but a real sprite would take about twice the time.
... And yes, your sprite is good enough. I love the crispness of the shadows and the lines!