Leading Lines and Curves
When looking at a picture, our lines look for a pattern or a lead-in to the subject. That's where lines can be highly effective in any composition. When our eyes spot a line in a composition, they automatically follow it from the edge of the frame to wherever it may lead.
The most common use of this technique is seen in compositions with roads and pathways. The image below shows a typical example with the straight pathway leading to the turn at the end. The idea behind the composition is simple, but the leading lines make it appealing to the senses.
Leading lines are not just limited to a set of parallel lines. Variations of the rule like in the image below show multiple leading lines moving from the edges to the central subject.
It's not just lines that can work with the rule. curves are equally effective as can be seen in the image below.
To follow the rule, simply draw a diagonal line connecting two opposite ends of the picture. Then draw connecting lines from the two unused ends so that they are PERPENDICULAR to the first diagonal line. 
