Three main rules of photography (as I have been taught in New York Institute of Photography) are:
I will try to use the following example to explain the rules. I am not sure that this photograph is the best example of the rules, though.
The picture above encompasses all of the rules explained on this page. What about the theme of the photograph and its subject? I think, it's clearly stated that the subject is the small jellyfish and the theme is about the sea or ocean. The story is in the tide, which threw away the small piece of life, may be even how far away it from "home" and safe waters. Sometimes a name of the photograph adds direction for thoughts and can be very helpful for unusual photographs. Though many famous photographers reluctant and even against giving the titles to photographs.
What about focusing attention? Ok, let's look at the focus of the image. What is in the focus, what is not? The jellyfish is in a sharp focus, but the ocean is blurred and distant. What else can we digest? The front plane of the image occupies the biggest part of the image and the eye is drawn to it, and there the jellyfish resides. So our eye doesn't wander in the image and doesn't leave (immediately).
Simplicity? The image is almost empty, there are only four "objects": sky, water, sand and the jellyfish. The people, gulls and even the sun was left out of the frame. So, the image is very simple and that adds space and focus to the eye.
And in conclusion, when all these rules are applied we have a very good photograph.~ Top ~