Look at the work of Claude Lorrain and Turner. Write notes on how those artists divide their landscapes into foreground, middle ground and background.
Referring back to the illustration already used for Claude Lorrain.
Lorrain used tone and colour to great effect to achieve aerial perspective. Landscape with Brigands 1633 – Even though this is a monochrome etching, the use of tone is striking in separating the three main areas of the image. The distant hills progressively become stronger in line and tone as they come forwards. The middle ground is more defined but less so than the foreground where all the action is, not only with the figures but with tonal values and detail on the near trees.
Lorrain predates Turner by well over a hundred years, yet Turner and his contemporaries have obviously observed and learnt from him. Turner used similar techniques in composition even though his style evolved very differently becoming a major influence on the Impressionists to come.