Don't know about the other guys, but i find the orientation of this picture wierd. If not for the words, i would had thought this should be a vertical orientated picture instead.
One cent worth,
If she is lying down, could ask her to arch her back more to show more of her slender build, and thus show the reason why u want compose the pose this way.
A tighter crop should able to let viewer concentrate on her features.
She's not lying down, you can tell by her hair falling off her shoulder, it's not, it falls almost upwards, and it's not her thumb i'm worried about, it's her fingers!!!:dunno: