Divide your field of view by thirds, both horizontally and vertically. Now try to place the subject emphasis at the intersection of two of those lines. Avoid bullseye compositions. For example, if you're shooting a landscape scenic, try to position the horizon either on the upper or lower third line rather than in the center. If you're photographing a person or vehicle, position them on one of the vertical thirds, either left or right side of the frame, giving them looking room. If a person is looking to their right, you would place them on the right side of the frame so that to the viewer they would be looking into the composition rather than out of it. With a composition of a person, unless you had a compelling reason, you would place their head at the intersection of the upper thirds to preserve a natural head-room. You want to use your composition to draw the viewer into the photo rather than out of it. So action should lead the eye in rather than out. A vehicle driving or a person walking from the left of the frame to the right would be positioned on the left to preserve action room in front of them.