In this watercolor painting for the challenge “Two Subjects,” I have horses and snow.

Sam and Sally, watercolor, 11" x 14"

As a general rule, having two (unrelated) subjects in a painting is like having two stars in a play; they tend to compete with each other for top billing.  When deciding what to paint, I usually decide who (or what) is going to be the star and make the other images co-stars, or less emphatic.  Then all the elements tend to “play well together.”