Visual Elements of Composition
When you look at the scene you're going to photograph, what do you see? The distinction between looking and seeing is perhaps the most important in composition. When you look at a scene, there's a tulip. When you see the scene, it's made up of colors, shades, shapes, textures, lines, and patterns. You see visual elements to be arranged and balanced in your composition.
I took art classes when I was in elementary school, and my teacher made us do exercises that I hated. She would give us an object to draw and tell us to draw it upside down. We would have to turn the object upside down in our heads and draw it on paper. It slowed me down, and it made me think too hard, so I hated it. Then she would have us draw it right side up. When we compared the two drawings, inevitably the one I drew upside down was better than the one I drew right side up. Why? Because my brain was thinking differently. I wasn't trying to draw a log on a table. I was paying careful attention to the lines, shapes and textures that made the log what it is. I was seeing, not just looking.
When we start to see instead of just look, things that bind us are no longer important. After all, if you're not just photographing a flower, it no longer matters what the boundaries of the tulip may be. You're not photographing a flower. You're photographing the color and texture of the flower--the straight line coming up from the bottom of the frame to meet the curve of the tulip, etc.
And this perspective of "seeing" also opens the door for the third aspect of photography--beyond exposure and composition is the interpretation of your subject matter--evoking feelings, causing people to think, telling stories, etc. For this kind of interpretation to take place, we need to be aware of what's going on in the scene as well as what's going on in us--we need to see.