Not trying to steal your work Andrea, just wanted to show you that you could use a gradient mask and then use the levels to lighten up the foreground, this gives the basic picture more definition. I think the
picture in the corner could be bigger. Make a feathered oval selection around the horse and the person and delete what you dont want before you paste it in, dont just go for reducing the opacity either, play around with the blending modes first, you might find something you like more. Hope this has helped a bit.