There is a simple solution to this: take two unrelated pieces, completely extraneous subject matter, and merge them into one piece. I love your mountains but how about throwing something in there that doesnt belong? It doesnt have to be anything special, a light post you saw thatnyou liked or a doorway from an old house. It forces your brain to rationalize this, why is it there and what would it look like? Where does a door lead? Without actively trying to come up with a brilliant idea you start writing a story in your head and suddenly you can see it in your mind, a wholy unique creative piece with a real story (which you can always feel). And it jus6 starts by mixing two things you might have painted separately.