Article: If you are taking a shot of your friend, make it of your friend, not of your friend at the end of the hallway. Then you won't have to cut a lot out of the picture when you come back and edit the photo after it's been uploaded. This is not quite the same as the 'golden mean' which is more applicable to painting and not photography.  Basically, the rule of thirds is "Mentally divide your viewfinder or LCD screen into thirds, using two vertical and two horizontal lines to create nine smaller rectangles and four points where the lines intersect."  Try to frame pictures so that the focal point of your subject is right in between or close by one of the four intersection points caused by the lines. Our eyes naturally gravitate to these four intersection points, not to the center of the photograph. Always work on a copy, so that you can always go back to your image and do something else to it, if you happen to have new/more inspiration. Go back to the friend in the hallway: the hallway is a lot of dead space. Crop the picture so that the person takes up a good majority of the frame, leaving a little background space to establish context. Sometimes, you need to leave some of the photo there so that the picture is in context. Are you going to print it out or have it on the web. You will definitely want more pixels to work with if you are printing it out, whereas a picture that is put out on the web will generally require fewer pixels. Crop the image accordingly. Like writing, it can be helpful to remove all the clutter and extraneous information. Crop that out so that what's left is a pure expression of what the image wants to be.
What is a summary of what this article is about?
Try to "crop" your photo as much as possible during the shot. Remember the Rule of Thirds when you compose your shot. Save the initial image so that you can crop it in more than one way. Get rid of the dead space. Know when not to crop. Consider what you are going to do with the image. Always ask yourself what the image is about.