rule of thirds
One Simple Trick to Better Compositions in Your Photography
Pye
Here is one simple thing to do before pressing your shutter to help you create more compelling photography.
A Useful & Concise Comparison of The Rule Of Thirds vs. The Golden Ratio
Kishore Sawh
Here's a great explanation about the two most discussed principles of composition in photography. Learn what they are, but then think if you should really be using them at all.
