The rule of thirds divides a frame into three equal columns and three equal rows. Placing a subject or horizon near one of the grid lines can create a balanced composition and leave useful space around the subject.
Use the grid as a starting point
For a landscape with an expressive sky, try placing the horizon near the lower horizontal line. If the foreground contains the stronger detail, give it more room instead. A portrait can feel more open when the subject looks or moves into the space in front of them.
Guide the viewer's attention
Leading lines such as roads, shorelines, or rows of windows can guide the eye toward a subject. Look for intersections between lines, strong edges, and areas of empty space before you press the shutter.
Composition guidelines are experiments, not rules to follow mechanically. Centering, symmetry, or an unusual crop may communicate an idea more clearly. Compare a few frames and choose the one that best supports the story.