How to Use the Rule of Thirds in Photo Composition. My wife has never liked horror movies. She developed a coping mechanism by looking at the lower left-hand corner of the movie screen during the scary parts. This is actually a practical application of the Rule of Thirds. Her theory worked for years until Ridley Scott decided to not apply the rule in at least two scenes in "Alien." The key to using the Rule of Thirds in photographic composition is...