Decide when to place someone in the scene.

This scene screams AUTUMN.

When there is an overwhelming amount of autumn color in a potential scene, use an appropriate focal length to really show it. Add a bit of fluff when some friendly clouds float by. It’s the kind of scene for which a circular polarizing filter was made.

Add a person when you would like to provide a sense of scale: person v. tree.

Tree dwarfs photographer.