Photography doesn’t have “rules” per se. There are some suggestions, though. On composition, it’s generally accepted that a photo should not divide in the middle of the frame. Better to put the horizon one third from the bottom or the top. The exception is when you have a perfectly mirrored lake and sky. Then the best shot might be to split it right down the middle. The rule of thirds derives from the golden proportion. 1:1.618 is the proportion of Nautilus shells, the human hand… and great photography (supposedly) http://goldennumber.net/ It’s hard to know when to break the rules. I try to keep the golden proportion in my mind when I’m taking pictures, but sometimes, the good shot breaks the rules.