Your finger rests gently on the shutter release. You're about about to squeeze one off. Why? Why are you taking this picture? Think ahead to when you get your developed photos back from processing - what do you want to experience? What do you want others to do in reaction to your photo?
Purpose or theme are important considerations in any quality photograph. If you want people to appreciate a pretty flower, you probably don't want to include the neighbor's garbage cans in the picture. If you are capturing a favorite vacation spot, you probably want it to look inviting - like the post cards for sale in the area. To give your photos the look you want, you will need to make use of several techniques which are described on the other Web pages. These techniques, however, are not ends in themselves - they are only a means to achieve what you had in mind for your photograph - your purpose, your theme.
Purpose or theme are often new concepts for a snapshooter. They take pictures every time the car stops on a family vacation - seemingly driven by some obscure law which requires it. They may expose several rolls of film in the belief that maybe one or two pictures might somehow be "good" ( I call this 'the theory of success through large numbers').
In Fundamental #3, you were urged to "Take Time To Think Before You Shoot." Theme or purpose is one of the items to include in that thinking session. Your thoughtful approach can be best guided by remembering the the following two statements:
You take a snapshot
You compose a photograph
Notice how the snapshot is just taken - and the photograph is composed. This is a key concept in one's evolution as a photographer - understanding that a quality photograph is a composition just like the other fine arts. They too, need a theme or purpose to be successful in their field of art, just like photographers.