I think this drawing and you as the artist have a lot of potential. You have detail in the head because of the shading you've put in. Put in that same shading into his neck. Once you've gotten the darkest areas shaded in, eventually work on putting in your lightest shades. Right now he's looking a little flat (his neck) but you can see his head looks nice and that's because you've put in the shading so just put that into his neck and everything should turn out nice. Just keep in mind to keep the direction of the light source the same otherwise it won't seem realistic.
Keep working on it, though!!
Opportunity is missed by most people because it is dressed in overalls and looks like work. ~Thomas Edison