hey
Hmm, doesn't really look like a grayhound to me :\. I'm not exactly sure what it is, but I was thinking that the ears don't stand out enough or something, and the folds around the mouth look odd and not of a grayhound, or maybe the neck is to big? or the shape of the head isn't quite right or something. But yea, things just don't look right to me :\, I might look into this more and see if I can be of more help.
editI done a
google on grayhounds, and I can notice many little things that I don't think are correct in your pixels. I think the angle of the neck is off (looks too upright) and that it shouldn't curve like it does in yours. I think you should also remove those folds around the mouth, and further define the mouth, as I think their lips or whatever are kinda black and stand out. The ears look a tad low, and the snout isn't long enough or something, and the shape of the eye isn't quite right. I also think you may want to think about changing the light source? and/or simplifying the color pattern or whatever of the fur, as I think it seems a tad hard to read.
But yea, there are a whole bunch of things, so just take a close look at a reference, as these are very important to have it look like a grayhound.
Anyhows I've kinda grown up around grayhounds, but nevermind, hehe.
another edit, and
Well I done an edit, and then after decided to break them down, as I thought it might be a nice idea to see if they look any more/less like a grayhound in there most basic form. Anyhows I don't think my edit is quite right yet :\, but hopefully it's useful.
cya