What a pose, with alert attentive ears and a soulful gaze on something (his master/companion?), fantastic portrait pose, with the delicately crossed hands, ooops I mean paws... And a gorgeous breed too, what is it???
The collar is the first thing I see though, maybe if you de-sat the collar it won't grab the viewer's eye unless it's got a symbolic meaning behind it or a special memory or something... Maybe try to darken the bright highlights in the TL cnr?
It's hard to judge sharpening really at these sizes, but gee the ears and nose look sharp as!!! Strange the eyes don't seem as sharp as the ears and nose to me... I wonder if that's due to the great seperation of the subject and the background that makes the subject look even sharper at the edges...?
Subject seems well exposed, maybe a smidge of levels (as in white level down a smidge, I wouldn't bring the black up)...?
His left hind might be a smidge close to the right side edge, but that's being a picky so-and-so... Just trying to provide C&C...
Good portrait, are we tempted to throw in a *soft* vignette?