Anytime anyone tried to convince me to do people I just shrugged them off saying "Naw - They don't have enough fur or feathers." They would laugh and drop it at that point. I also did not accept commission work because my best paintings were portrayals of things that I was passionate about - not someone's pekinese. Unless it was a wild critter, I wouldn't paint it; and I did well enough financially by painting what I wanted to feel free to turn down offers.
Okay - you asked for it! Your pastels are lovely! They reflect your love of horses perfectly. Your proportion is good - That's what most people mess up on when depicting animals. My favorite is the third one in from the left (top row), and I believe it's because the color is more saturated than the others. Since I've never worked with pastels, I have no idea how difficult it is to get good, strong coloration.
There are two things that strike me as a bit off. Number one is that I can tell that you have no interest in spending much time doing backgrounds. I can relate - lol. But a good subject needs care on the backgrounds as well. They don't need to be detailed. Try taking photos of a focused subject where the background is somewhat blurred. You can always do something like that for a background that complements your subject. A darker background for a light subject and a lighter background for a dark subject. I always start painting what is farthest away and work my way forward while blending, taking care that my subject doesn't look "cut and pasted" onto the background.
Number two is subject "depth". Many folks make the mistake of thinking that all shadows are black. You
didn't, as I can see on the man's shirt. Inner folds are a deeper blue than the outer folds. So - You're one step ahead already. But I think that you could use more shadowing and highlights, and more saturation and contrast in general. Just my