Because photographs by their very nature are two-dimensional, it can be tricky representing a three-dimensional world through photos. One tip for creating this illusion revolves around the use of leading lines (or diagonals). Leading lines within an image create the impression of a third dimension by adding depth visually.
Leading lines are often linear or curvy forms and shapes – natural or artificial – that subconsciously lead the viewer to the main subject within the photo. The leading lines seem to pull your eyes along towards what the photographer wants you to see. For example, a pier leading off to the ocean, a road leading into the unknown, maybe a white picket fence, cluster of buildings, or strategically placed objects can all add depth to a photo by leading the viewer’s eyes to the main subject or a point in the photo.
Here are a few more examples.
Check out more quick photo composition tips in my library.