Here's a brief overview of the concept of leading lines in photography. It's a technique you can easily use with any camera to create stronger images.
A winding road or a set of railroad tracks leading off into the distance is a clear example of a line that grabs our eyes and draws us deep into the image. This kind of line gives a photograph a sense of motion and an illusion of depth.
Road to Carti - Kuna territory, Panama
A leading line could be any area of contrast in the image, it could be the edge of a building, a shadow on the ground, the ridge of a hill. And by changing your camera position you can control where the lines actually lead to. For example a road can look more or less curved depending on which side of the road you shoot from. And in the photo of the Bonavista lighthouse (see it further down this post) I walked around the lighthouse and closer and further to the fence until the curved line of the fence pointed at the lighthouse itself.
In this photo, it's the river that grabs our attention, leading our eye into the details far in the background.
Duffy Lake Road - British Columbia, Canada
Keep an eye out for multiple leading lines: This photo combines the layered landscape we covered in MotoJournalism Book One with several lines that draw the eye along the vine-covered fence, and through the rows of agave to the middle ground. You could even count another leading line along the row of shrubs where the two large trees sit.
Costa Chica - Mexico
But line in an image can also be implied, it doesn't have to be a physically continuous single line. The receding arches here, and even the iron lanterns point directly to the band in the middle.
Once we're able to quickly see potential leading lines in a scene in front of us we can actually compose an image in such a way that we can decide where the viewers eye will go.
This photo of a meat market uses the perspective of the corrugated iron to point directly at the woman and the butcher at the back.
Another example of using converging lines to point directly at a subject.
This is one of the reasons I tend to shoot things off-center - I find it more interesting to make the eye travel back and forth across the whole photo.
Another example of a sweeping S-shaped leading line; your eye starts at the man in front and is pulled toward the man further down the road.
Here are two clear examples of structures that move your eye from one part of the image to another.
Costa Chica, Mexico
Another example of an implied line rather than a continuous physical one. The line of people suggest a line that leads your eye from the foreground deep into the background.
Leading lines can run in any direction, from the background arching around to the foreground in this case.