According to Cemal Emden the hardest thing for him as a photographer to explain is why he is photographing the object he’s focusing on. Understanding how to focus on it is a technique and it improves with experience.
For reducing distortion in photos, one must use symmetrical lenses, like when photographing a high rise. But for images with distortion, one may use retrofocus lenses, like when photographing a landscape.
Here is a brief overview of what he talked about with a compilation of his works.