A popular topic during my one-on-one workshops is composition and many photographers have heard about the rule of thirds – I personally think the rule of thirds works better with the older aspect ratios 4×5, 8×10 as the frames weren’t as wide as the modern 35mm frame with its 2×3 aspect ratio. Yet, the Rule of Thirds is nowhere as flexible and true to nature as the Golden Ratio, which in turn is based on the Fibonacci sequence. Now, no one wants to do math when they’re out shooting, so there are other methods…
…like the Golden Ratio (Golden Mean), or the Golden Spiral, or even the triangular method, all of which one can use in Lightroom as a crop guide overlay. I personally swear by teaching the “Diagonal Method”, as it allows for very dynamic compositions and the system is easy to understand. follow the link for more info and examples. What’s really cool about the Diagonal Method is that it is so insanely easy to use, once you got the hang of it.
Like any other rule, it is not hard and fast… feel free to experiment and put it through its paces by breaking it – that’s what great artists did for centuries to come up with inspiring pieces.
Lightroom has the guides built in, if you turn on the crop tool (R), you can change the crop guide overlay to diagonal tools > crop guide overlay > diagonals
Photoshop CS6 has a bunch of crop guides built in as well, and you can download a smart vector objectby simply clicking on this link