"Golden" Composition and Cropping

Behold the Golden Spiral (pictured above), Golden Angle, and Golden Section: composition and cropping principals - excellent PDF article. One of the areas I'm always going to need to work on is composition. The only way I have ever used thus far is the rule of thirds. I know that rules are made to be broken and great photographs often do just that. I guess I want to learn the rules first and then make a conscious decision to break them.

I had never heard of these concepts before I stumbled upon a Lightroom video tutorial which shows that each of these are available as overlays in the Lightroom cropping tool. If go to crop an image and then hit the letter "O", you can scroll through the different overlays to try to compose your crop. If you hit "Shift-O", you can get different variations on each overlay. The Golden Spiral has been the one I've enjoyed using most as of late. I didn't realize Lightroom had this feature and I've found it helpful to try to think of different ways to crop an image.