Composition
What makes a good photo?
Composition is part of it. This is what is in the field of vision, how they interact with each other, how they are framed. What dialogue the light and dark areas create. Small changes can improve or break the composition.
Theories can help us. Off the top of my head - leading lines, rule of thirds, symmetry, negative space. When I stepped up my shooting, I tried to follow the theories religiously. With my lifelong learning and working in a logical way I needed to grab on to anything that could help me transform photography into a process. The theories broke down photography into bite size chunks I could work with.
Now I tend to use them less consciously. They’re still there but I don’t think them out loud so much anymore. Like many things, the more you do it, the more it becomes second nature.

Leading lines
Use of lines through the image leading to a vanishing point.

Rule of thirds
Placing an important element a third of the way into the image.

Symmetry
Uniformity, the elements are mirrored.

negative space
The use of empty space in an image.