Caitlin, Very nice work in color. Color is very challenging, isn't it. One thing you might look at, and I am totally nitpicking here, is the horizon line. The line you have between the green and the blue. I realize this might not be the actual horizon, and it isn't in any way crucial to be accurate about the horizon (I rarely am!) but thought I'd throw this out for you to think about.
If the viewer is low, like if you are looking at scenery seated or squatting, the horizonline will be low and one will see much more sky than ground. As you , the viewer, get higher, you see more ground, less sky . So, looking at that horse, I feel like I am lookind down at him from at least a standing position, which would bring the horizon line up higher. It kind of makes it currently look as if he's about to fall of the edge of a green ledge.
Don't take is as bad. Artist' liscence allows you to manipulat such things, but having an awareness of this is good for your growing skill.