Try using a wide angle lens to make a portrait. It's a very dramatic, and very unusual, way of photographing someone. For this low angled shot of a Karo tribal member in Ethiopia, I used a 14mm lens. The great thing about using a wide angle for this type of shot is that it has tremendous depth of field even at a large aperture, and also the background becomes an important part of the shot.
As much as depth of field is inherent in wide angle lenses, when you place the lens extremely close to the subject and you focus just a couple of feet away, as I did here, you still need a small aperture to insure the background will be as sharp as the subject. Therefore, I used f/16 here along with an ISO of 400. I hand held the shot.