Ask HN: Photography Hacks

I have always known about the rule of thirds [0] and golden ratio [1].

I recently learned of rabatment of the rectangle [2], lead room [3] and head room [4].

What other "rules" of photography or modern hacks do you find worthy of adding to your repertoire?

[0] https://en.wikipedia.org/wiki/Rule_of_thirds

[1] https://en.wikipedia.org/wiki/Golden_ratio

[2] https://en.wikipedia.org/wiki/Rabatment_of_the_rectangle

[3] https://en.wikipedia.org/wiki/Lead_room

[4] https://en.wikipedia.org/wiki/Headroom_(photographic_framing)