In photography, there are several rules of composition. They include the Rule of Thirds, The Golden Ratio, The Golden Triangle and there are several other guidelines photographers should follow. All of these rules or guidelines are there to help photographers create a more pleasing photograph. The only place a photographer has complete control is in the studio, while on location the photographer still maintains complete control over the models/subjects but not the lighting and environment.
All of these rules and guidelines actually do work, they force the photographer to create a visually pleasing photograph, but there are many photographs that are visually pleasing and break every rule of composition. These rules aren't the end all and be all of composition, but they are a great place to start. If you're in a studio setting, keep try to apply these rules. If you don't have control over your subjects, be aware of these rules and make that photograph if a scene that follows one of these rules appears in front of you.
Here are a couple of videos that describe the rules of composition and their origins. The first video is Photograph Composition Basics, the second is Classic Art Designed for Photographers.