Jade, when I checked the forum to post mine, I noticed that "great minds think alike" as we picked the same reference! That is very nice, but I agree that some darker values would be helpful.
This is done entirely in Inktense, which was a slow and frustrating slog. It is 7 x 9, in a Strathmore Visual Journal, which is not good paper for watercolor, so I am "using it up" on ink. I did a few horse heads, but never a full body before, which I found to be quite challenging.
I agree with Wayne that your drawing could use more darks to get a wider value contrast but I have also found that can be quite challenging using graphite. It just doesn't go that dark. A soft lead (like a 6 or 8) might help or sometimes a carbon pencil can be used for the darks.
Aside from that, I love how you captured the movement in the horse. Not an easy reference.
Joy, you did a great job on the horse as well. The feeling of motion is there and the result is wonderful. I also like how you have the dust being kicked up by the hooves.
Inktense isn't for everyone though. Use if you like it, move to something else if you don't.
Anne, that is just darling. Really appreciate the colors and the textures. The scanned image looks fine to me.
Jade, I often do not save enough lights and use too many middle values. Pencils only contain graphite and clay, with higher B pencils having more graphite and less clay. Pencils have never had lead, and it is a common misnomer. Here is a photo of a pencil value chart.