The background can help or hinder your picture.
However, it's very hard to pay attention to what is happening back there.
Check the background and do the following.
If it's not good, change your vantage point.
Push the background further away by using a wide-angle focal length.
Or, bring it close by using a more telephoto focal length.
Use a wide lens opening, such as f/1.4 on a 50mm lens, to blur the background.
Use a smaller lens opening, such as f/16, to have the background sharper.
Things in the background may merge with the subject.
The classic example is a telephone pole behind a person's head.
Also, make sure the horizon line does not line up with a person's eyes.
The foreground is often not used well.
If your photograph is not being improved by an empty foreground, then do the following.
• Change your vantage point.
• Zoom in.
• Place something in the foreground, such as shooting through the cattails on the edge of a pond.
Use something in the foreground or background to frame your subject.
For example, place a tree on one side of the picture.
Or, place your subject in front of an out of focus arch of a rose arbor.
Close one eye to judge how a scene will look as a photograph.
You can add to the feeling of depth in the following ways.
Use receding or converging lines in the picture.
The lines could be a road, for example.
Add depth by having lots of separation between the subject and background.
There are three ways to do this.
1) Make the background out-of-focus by using less depth-of-field.
2) Make the background lighter or darker, or a different color, than the subject.
Blue tends to recede, as do lighter colors.
3) Use backlighting or side lighting. The bright edge on the subject will give a feeling of separation from the background.
Haze in the background is a cue to our brain that the scene has depth.
If you add something of known size to your photograph, the viewer will be cued as to the size or distance of the subject.
The small person in the distance, with a much larger person near the camera, is a strong depth cue, for example.
You may wish to remove depth.
Do the reverse of the above.