This is a Drawing by Numbers portrait--no numbers, no directions, I just started out with an outline sketch of the drawing and worked on my shading. These are the first two horses so far, 3H through 6B, I think they're quite dreadful. About 3 hrs each, and I'm hoping I would've spent longer on them instead and made them look better.
I think they look great! I love your shading. Just one thing - I would try to work on the nostrils more. The sketches don't have much as far as the nostrils, so I would look at another reference picture and tweak it from there. Do you see what I mean? They don't look as realistic if they are little crescents. That is, if you want the practice. Nice job, though!