Well, I'm also a beginner, and the only contest I ever enter is the county fair

, and I dont know anything about the contest you're entering (so really, should I even be giving you advice? :er

, but I've seen a lot of these. But theres nothing new under the sun, so...
Yours is nice and clear. But it bothers me (and its probably just me) that the horses forehead goes nearly straight down through the picture, instead of sloping, because when I think of horses I think of their forehead sloping because of the way their head is attached to their neck. I know it's just how the horse is holding his head in this picture, though. It's probably just me, though.
I guess I dont have any strong feeling about it either way.
Good luck on your contest!

And welcome to TPF.