Composition is not just about positioning subjects in your shot – sometimes it is more about positioning yourself as a photographer in order to make a more pleasing arrangement of subjects in your frame.
Height is one way to alter your perspective as a photographer. In many cases a shot taken from or just below the eye level of your subject is ideal and creates a more intimate shot. However mixing it up can also leave you with a creative and interesting perspective.
Looking down on someone looking up at you can also be powerful – and looking up from the ground at someone can also dramatically alter the look and feel of the shot. Of course shooting height isn't the only element you can change. The distance between you and your subject is another factor worth experimenting with. Shooting from a distance can show your subject in their environment – while shooting up close and tightly framing your shot can help to isolate them from a distracting background.
One last way to alter the composition of an image by moving yourself as the photographer is to move around your subject. While shooting a portrait from in front of a person is probably the most sensible place to start in most instances – a side view (portrait) or even shooting from behind can create some interesting shots.