Choose a subject in front of a background with depth. Select your shortest focal length and take a close low viewpoint, below your subject. Find a natural point of focus and take the shot.
You’ll see that a very wide lens together with a close viewpoint creates extreme perspective distortion. Gently receding lines become extreme diagonals and rounded forms bulge towards the camera. Space appears to expand. The low viewpoint adds a sense of monumentality, making the subject seem larger than it is, and tilting the camera adds to the effect as vertical lines dramatically converge. Not the ideal combination for a portrait shot!
Shot Take on Nikon D750 with a wide angle lens, shot from a low viewpoint ISO 1250, 18mm, F5, 1/250 seconds.
I can see that the perspective is distorted in this picture. The feet of the subject appear larger since they are the closest to the camera and the head seems too small for the rest of the body. If I were to be taking a portrait shot this is not an angle I would use. However, if I wanted to convey and emphasise the monumentality of a subject then this angle could be useful.