It depends always on intention of a photo what we will want to show. If you want to have a snapshot of your family during a homly get-together, normally you do not set a great store on the picture art. On the other hand for our professional photos you want to bring your object in the middle of concerns.
Prior to talk about adjustments of a picture content I'd like to say something about focusing objects on pictures.
Supposing we want to focus on the eyes of a person, these should be carved out on the picture. Everything what points away will run contrary to our intention.
A beautiful, glittering necklet an additional person or a fluttered background can direct the view away.
On a schematic simplified way you can visualise it by an black point on a white screen.
If you want to show only one tree on a white screen, which is not easy in nature because there are lawns, fields and possibly ways. You can use perfectly a way to direct the view to the tree.
Returning to our scheme this example consists on a point (tree) and a line (route) on the screen.