Almost there ^.^

In most respect its quite a good picture, a great idea and well executed.

Although the hair needs to be more defined. Think about the weight of the lines - thin, thick, narrow, wide etc because it seems like the darkest tones is the lineart for the eyes and the head/neck. So do the same sorta tone for the shadows in the hair, so it looks more refined. Plus the light reflecting off the hair is usually zig zagged slightly rather than a straight edge....but thats just typically speaking.

I have to disagree with the comment below by Hoboweasel, the mouth doesnt need to be any larger, but i would suggest have a slightly narrower shadow under the bottom lip. A nose wouldnt do that much difference either. It seems to work pretty well without. Well done, keep it up =D

It's hard to get faces down, don't worry... xP

Try making the head a bit rounder, mouth a tad larger, the face longer and closer to the shoulders (just a bit though), also a nose would help (though if you wanted to draw this way out of style I would still recommend making the face a bit longer). But you pretty much have the proportion down otherwise. The light reflected off their hair indicates they're in direct light, so keep that in mind... Nice work though.

<3<3<3

This is a really beautiful piece of art! She seems to be floating in som kind of endless void, which makes her look innocent and..well peaceful. Nicely done with the hair and the circle of flowers around her. :D
Kinda makes me want to hug someone. ^^