I agree with Lanty, you could fix the lighting, and one way to do that is on a new clipping mask layer over the horse, sleet the color of the light from the background and with a large soft brush go around the areas of the horse that the light would hit. It's a little difficult to get lighting right when the background has such vibrant colors, like sunsets.
Another thing is adding some highlights and flyaways to the tail. Select the main color of the tail and lighten it up, then with a small hard brush with pen pressure on, create some strokes of hair. Usually horse's hair is all over the place, and now in one solid block.
It's super pretty! Always remember to check your light source on your background though. In this case it's coming from behind the horse so it would be mostly silhouetted. You did a great job with smudging and the overall composition is great!!