The rule of thirds is widely considered to be one of the most important first techniques you can learn to create better compositions and help you progress from “taking pictures” to “making photographs.”
Don’t let the name throw you, though. It’s not really a rule. It’s a guideline or principle for composition that’s been used by artists for a long, long time. It works for landscapes, portraits, wildlife, and every other type of image, even abstracts. Not every picture has to use the rule of thirds, however, but it’s a great place to start when you are looking through your viewfinder and wondering what to do next.
So what exactly is the rule of thirds?
You can read the whole article at Petapixel.com.