In a previous post, we discussed three styles of composition and the value of making use of all three. Within that spectrum of composition styles you can use, photographers make selections concerning what they want in focus and out of focus. This selection can have a significant influence on your composition: how much of your scene do you want in focus? You may want everything in focus, only some aspects of it in focus, or you may even select to have all of your photograph out of focus, especially in abstract compositions.
Consider the two photographs above. Both photos were taken at basically the same time, with all the same camera settings. The only change was in the point of focus. But they are different compositions and different photos. I took several like this, focusing on different parts of the same scene. One day, I'm probably going to display three of them together.
So when you come across a scene you like, don't just shoot and leave. Consider what kinds of focus selections you can use, and try different things. You may find that the third or fourth thing you try is actually the best.