One of the marks of a lot of good images is the ability to make a two-dimensional photo have the feel of a three-dimensional scene. This excellent video tutorial will show you how to take advantage of the way the human brain determines distance to give your images a deeper sense of depth.
Coming to you from Chris Sale, this great video tutorial will show you how to use perspective to add a sense of depth to your photos. Though this particular tutorial is oriented toward landscape photography, the lessons apply to pretty much any genre. The idea is learning to actively take advantage of one of the ways our brains determine distance: relative size. By placing an object of known size close to the camera, you can force the brain into developing a sense of depth in the photograph based on the relative sizes compared to other elements, thus giving the shot a more three-dimensional feel and helping your viewer's eye to travel through it. Check out the video above for the full rundown from Sale.
If you would like to learn more about landscape photography, be sure to check out "Photographing The World 1: Landscape Photography and Post-Processing with Elia Locardi."