In reality a photograph is a flat 2 dimensional but giving it perspective gives it structure and helps lead the eye. There a visual tricks you can use to achieve this. Linear perspective can be emphasized by converging lines which extend into the distance. Diminishing scale in use of things which get smaller the farther they are away. Aerial perspectives particularly with leading lines draw the eye into the image.
Aerial Perspective : This is an excellent example of aerial perspective, The eroded creek leads the eye the lightening in the tone and the hills rising in the distance imply depth.
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