2. Enable Grid Lines
Put simply, it dictates that you should place the subject of a shot in one of the four intersections of lines on a 3×3 grid.
However, in order to get the most out of the rule, you’ll need to enable an on-screen grid so you can see the four intersections. Gridlines are also useful for other composition issues, such as keeping the horizon level or making sure walls and buildings are at precisely 90 degrees
To turn these on, go to Settings > Camera > Grid and slide the toggle into the On position.