To begin, I really like your style, and I also love how you shaded this. This is one of your better works, partially because this type of shading with this style gives it more depth and dimension. You shaded the dark places nicely, but in some places you should've either left them blank or lightened it. Try to imagine a sun or moon as a light source, that should help with shading. I'm having trouble with shading, personally. I'm studying wolves a little but I focus more on cat anatomy, so I'm not an expert, but for the most part, anatomy is good. However, the chin is a bit too big, as well as the head. The fur on the tail is a little clumpy, and on the butt, too. (lolbutt.) Fur doesn't go in one direction, but on the butt it usually lies flat, instead of going in two directions.
All in all, I think you're on the right track. Just a ittle more practice with the face, proportions, fur and shading. I love this. He's so adorable. ;u; Looking forward to starting the art trade with you! ~