The overall image itself grabbed my attention right away. The subject and the setting compliment each other very well. I don't know if you did it on purpose but there are a lot of really interesting angle interplays with subject and setting.
The texturing of the set looks very good. Only my opinion but I don't think Aiko was meant for the super realistic stuff.
I'm guessing that you don't use a camera. I don't but I should start. The camera is what gives the whole piece better depth, blurs the background a bit.
The girls is great. Her pose is well done and her expression nice and "soft".
Again, I am just guessing, but you may have the ambient shader on her clothing on white? If you do you may want to cut it down to a smaller # or switch to black. I have had the most luck with the matt setting and usually black spec and ambient, with the diffuse down around 75%.
You have a very good eye. I really like how you zoomed in and didn't try to get the whole girl in frame.
Keep it up!