A long time friend of mine and a great musician Damon Grant has a habit of always pointing to something or someone in the photos that he posts on Facebook. There is always something striking about the photos even though they are usually just random snapshots from a social event. The reason behind this is VISUAL PATHS. By pointing to something he is creating a strong visual path to guide your eye through the image. Instead of just staring at random faces in the photo, the eye is guided along a path which creates movement and a natural flow. More examples and information can be found in this great article by iStockPhoto.com.