Thanks for making this wall. I've always loved Takamichi's artworks. they're sooo happy and breezy. :3

Hmm, two comments I would make - first off the wall just seems slightly too curved - as in the part just after the character seems much more an acute curve than the part she's sat on. That may be somethgin of an optical illusion though :)

The bit I do think you shoudl tewak is the shading - she needs more under her. The wall has recessed bits with quite sharp shadows, and that would tend to suggest that she also would cast a stronger shadow on the wall. It is actually slightly confusing where the light source is coming from, but her lack of darker shadow (especially close to her butt) does give her a slight floating feel, which seems just a little too unrealistic.

Hope that helps :).