Well, I don't know anything about shading techniques (or really anything about drawing digital at all), but a couple of other things pop out. Eyes need a little something to make it look less like Ski's been hitting the coffee pot with a straw -- but not too much: the whole feel is one of eagerness, and the expression adds to that. Something about the mouth seems a little off -- I'm not sure what -- some proportion or maybe what is hidden and what is not -- but maybe after the nose and chin are more defined it will all seem right. I can't really say, I never seem to get the mouth right.

I really like the ears a lot. Also the posture caught my attention .... it adds to the canine eagerness the whole thing evokes. The colors also add to the bright feeling.

I don't know that any of that was helpful, but I tried ^v^

I'm looking forward to seeing how this turns out when you are done!