BREAK THE RULES
The bottom line is: There are no rules. If an image works, it works; if it doesn't, it doesn't.
At one of my exhibitions, a person with a doctorate in photography was looking at one of my shots and I could see she was puzzled. I asked if I could help. "I can't believe this!" she replied. "This guy has the horizon in the middle. It should be one-third sky, two-thirds foreground. But this really works!" That person didn't know I was the photographer, so I simply replied, "Isn't it lucky he doesn't know the rules, or this shot may never have happened."
There's only one essential rule: Make sure you have film in your camera! Although I once met a photographer who sometimes left the film out because he wanted to enjoy the privileged position of being a photographer without being disappointed with the results!