Most people with a camera can handle the left/right, up/down dimension of an image. True photographers have a handle on the depth their images convey. Doing this requires awareness and control over the elements supporting the primary subject–the foreground, when the primary subject is distant; the background, when the primary subject is close.
One of my favorite things to do in fall is look for striking leaves that I can make stand out against a soft background of color and/or shape. I found these leaves beside the Merced River near Fern Spring. Positioning myself so the leaves were juxtaposed against a stand of mature evergreens upriver, I experimented with different apertures until I got the effect I wanted. An extension tube on my telephoto lens allowed me to get closer and soften the background further.