I think your biggest issues are with the photo styling. First you shouldn't have taken the image on a surface that indents. The second issue deals with the issue of shooting a non-quality shoe from an angle that shows off the shoe's flaws.
Specifically the stitching up the back of the shoe is both off center and uneven. I would treat this like a portrait where you have a person with an asymmetrical face where this is like a straight on shot. I would have angled the shoe in such a way as to make this stitching less noticeable.
Don't share the comment about the stitching with your GF as it could be a very expensive comment 
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