I'm not much of a photographer but I'll comment on your shots.
#1 doesn't do much for me. The subject isn't too interesting and it's very contrasty. Nothing that makes me say "wow."
#2 is similar. There's an obvious focal point, but the sky is blown and there's nothing about the photo that makes me say "wow." The horse is beautiful though.
#3 is more interesting to me. It's sharp and clear and the horse it pretty but again the sky is blown. And I keep wanting more in terms of interest.
#4 is my favorite. It's interesting and unique but I don't think I'd have the focal point in the center of the shot. Also it's a little noisy. I'd have shot that one at ISO 400 (at the max) and used a slower shutter speed. Unless the wind was really blowing the branches around I see no point in needing 1/500 shutter speed.
#5 is a pretty silhouette.