The use of a Leading Line in a Composition draws the viewer's eye through the photograph along the line. This compositional technique is really no more complicated than that.
Not every line is a Leading Line. Rather, only those that actually tend to draw the viewer's mind-and-eye through the image.
As with Frames, there are many forms of natural Leading Lines and man-made Leading Lines, including roads, bridges, rails, trails, paths, river banks, etc.
Take a look at the photograph in this collection made at Sainte Flavie, Quebec to see an example of a not-so-obvious Leading Line. Because of the arrangement of the figures, the mind tends to draw an imaginary, curvaceous line through the figures.
Perhaps you can find similar opportunities for not-so-obvious Leading Lines in your own photographs.
© Jerry Weimar Photography