Off to a good start. The horses look generally proportional, so that's a plus...Love the expression on the head shot. Even for a basic drawing, you managed to catpure the horse's personality well. As with what everyone said above, start experimenting with shading look for the darker aspects of the photo and try to play with shading and altering the firmness of your pencil strokes.
As for hooves, you picked a very challenging angle to draw hooves from. I'd practice drawing from photographs of the side of the horse, not angled towards the camera. You may also want to find pictures of just the horse's legs and draw them at a larger scale for practice to get the shapes down.
Hope this helps. Can't wait to see more of your work. :)