When setting up your subjects to photograph, avoid placing them in the center of the frame. Place them to the right or left of the frame leaving the empty space in front of the subject so they have room "to look into".
Try using the rules of third.
Placing your subject in one of the spots circled in the above image.
Make sure your horizons are straight, and do not put your horizon in the center. Make a decision on which is more interesting, The sky/skyline or the foreground.
Use diagonal lines to to draw the viewers attention to your subject.
When photographing a group of people place them in a grouping that resembles a triangle or a circle surrounding one or two of the subjects.
Watch out for trees and power lines "growing" out of your subjects head.Try to use backgrounds that are clean around your subjects head and aren't cluttered in the background.
One last tip...Do not place your subject in the direct sunlight or facing the sun. Always place the sun behind or behind and off to the side of your subject.