Jesus, any sketch that uses the hatching technique as shading catches my attention. I like the calm yet somehow unsettling mood that's being placed by the expression of the girl. She looks relaxed, yet her eyes are looking behind her, as if she's double checking something - common for people who are unsure or a bit confused as well.

The only suggestion I can point out in this artwork, is how her neck is placed a bit too close to her chin. If her head was drawn a bit more to the left, or the neck drawn more curved then it would definitely look more realistic, as I don't think a humans neck can be that close to it's chin.

Other then that, kudos for the neat sketch.