White balance could be improved a bit; it has a slight yellow cast to the picture, and you could add more contrast and remove the shadow on the right side.
After some quick corrections, you get this:
compared to:
I think you could also have better lighting conditions. The lighting here is flat. Adding more contrast, though, does help.
I have essentially halted my uploads because of the high rejection rate. It's not worth the time required to edit, upload, and add titles and keywords just to receive an unwarranted rejection.