If you want to work on several pieces at once, I am the last person to call you on it. Indeed, this path can lead you to victory so don't sweat it as long as you stay productive
Regarding your current piece: Assuming you are referring to Belle form Beauty and the Beast, I'm pretty sure she wasn't a princess. Nor was her name Belle unless you're working from a French translation...
As always, you've put your best foot forward with her luscious mouth. Her nose requires some more attention but I assume that you already know it. Once you address the nose, this should resolve the eyes and the rest you can do in your sleep
Now I have to ask if you know the characters that you are illustrating or if you're simply gleaming off the Disney versions. Because if you haven't read the Brother's Grimm or Hans Christian Anderson, etc. then you can hardly do right by these girls. Someone of your talent shouldn't feel constrained by the whitewashed spin that Walt threw on these classic tales... Get to the source and find the real meat so you can use your art to cut straight to the bone
But that's only my opinion. You've been doing solid work without it, but I can't help but think that if you were exposed to a pure source that you might draw more strength which would reflect in your work
Afraid of Sunlight - http://www.ledante.com