I need to begin this discussion by making a strongly held point, that most people intrinsically know good composition and will probably do better than say “the rule of thirds” or similar composition “rules”, just using their eye. However I must admit I have been having a bit of fun trying figure out why the Fibonacci Spiral (its called the Golden Spiral in Lightroom) might be a composition aid? The ratio behind the fibonacci series is roughly 1.618, so it doesn’t neatly cut a shape into one third two thirds but it is close. so I have heard this gold number referred to as the rule of thirds on steroids. More importantly it has been known to artists as the Divine Proportion since the renaissance, and often used unwittingly by artists and architect before that.
I have found two ways to use the spiral as a guide. Firstly using the inner focus of the spiral to target the main point of interest (the ducks head in this example). So you need to toggle the orientation of the spiral overlay (using <shift> O repeatedly in Lightroom. Alternatively I have found the outer arc of the spiral a good place to line up strong contrast changes, letting them follow the sweeping curve (not shown here). While this second approach doesn’t draw your eye to a specific focus point but it does guide your eye around the image, in a pleasing way. The android app ProCapture has an onscreen Fibonacci spiral to aid composition, which is also fun on the phone because you see it as you are taking the photo..