This is a beautiful piece, but there are some inconsistencies in perspective, like the size of the bridge compared to the size of Amaterasu. I don't know if you intentionally made her larger, but it looks a little awkward. Also, the foreshortening makes her look a bit stocky too, adding more shadow to the neck and body could help slim her down and add length, because she is on an angle.
I have nothing to complain about with the background, it is beautifully done.
Overall, any of the inconsistencies in this piece are subtle, and would just take some gentle tweaking to fix them. Keep up the good work!