I think it's pretty good. Creating color from a lack of color is one of the more challenging things one can do.
I have only a couple of suggestions, and they're light ones. If you're using Photoshop, I'd use the stamp tool to paint out the creases and scratches. Of course, that's provided you don't want the creases and scratches.
Then, and I'm not sure how well it would work, but perhaps find an image of grass that has all the different colors of grass included and then set it as a layer that covers all the grass already in your image, and set the layer properties to Multiply or something the like and then play with the opacity. That might give your grass some life-life color variation.
But kudos for the painting of the fur on the dog.
Not an easy thing to do.