Keep People Away from Sides
As the sides of your image in the viewfinder are apt to curve, shoot people away from the sides and corners of the shot. Put them more inside the photo.
Using these tips will help you take amazing photos with a wide angle lens. Take a lot of different shots with the wide angle lens to find out what the effects are. Try some vertical shots, and some from below and some from above to see how the lines are affected.
For additional tips on wide angle photography, check out the book “Wide-Angle Lens Photography: A Complete, Fully Illustrated Guide” by Joseph Paduano.