Also, I think the piece would be much more impressive if you positioned her in a way to show her hands, speaking of which, I think her elbows need to be higher. 

 

And her legs are quite short! even for a cartoon character, it just looks odd you know? 

 

Another thing, why do you see the same amount of bow on either side of her head when her head is turned?  And the texture of the hair isn't really flowy.

 

I'll see if I can do an update to show all these things :)

In the meantime, it'd help if you explained a bit why you made this and where you wanted to go with it and such things so I know what you want instead of just imposing myself on it.

 

 

Edit:  well here's how I'd go about it (instead of just posting an edit, I decided to save all the steps so you could seewhat I changed more)

1. Your original

2. I sketched a little stick figure to fix proportions (make legs longer) and reposition arms.

3. Tried to clean up a bit and realized that the pose looked unbalanced, like she was gonna fall over.

4. More sketching.  Congratulate yourself if you managed to look at all the colors without throwing up.

5. Made a clean outline around the pose that looked most natural

6. Cleaned some more and fixed a wonky arm - it's good to take things one step at a time because if I had everything else done I wouldn't have bothered to fix the bad arm.

7. Just basic shading with the lightsource from top left.

    When you draw in the clothes it's important to put different textures on things, because then it'll just look like painted skin.  Especially think about how the clothes would fall on the girl - for example, there's not a shirt in the world that would stick in between a girls boobs and make a deep shadow like in your original. 

   I also blocked out how the hair should be, because it was skewed in your original - her face was turned, but hair still looked like frontal view.  And I made a little sketch showing some hair being pulled back to the bow.  Girls don't usually put a random bow in their mass of hair, it needs to be holding something.

 

Hope this helped, looking forward to your update.