Leading Lines: I will admit that my example is not great for leading lines, but it kind of shows the idea. Look for lines and curves that take your viewers eye across the image or through the image. On this photo the natural lines of the wood draw your eye across the photo and may hold your interest just a touch longer than if there were no lines at all. (and yes, I know that caterpillar is not tack sharp, the little buga would not be still!).