…you have to understand the rules to use them. (I'll be using "rules" and "guidelines" interchangeably here.)
It's just as powerful to understand what makes the rules tick — what the reason beneath the reason is — so you can use rules and tropes to your advantage as it is to understand the rules and intentionally break them for a specific reason, or to understand the tropes and intentionally subvert them.
For instance, I recently saw a post on here that said "How do I make my villain sympathetic?" I see a lot like this: "How do I execute this thing that I think is generally characteristic of good storytelling?" But I doubt everyone even understands why you want a sympathetic villain and if a sympathetic villain, or a human villain at all, works for your story. It's important to understand why you want to use a "rule" or else the execution will undoubtedly be uninspiring.
Do you want a sympathetic villain because they're just better? Why are they better? They make you feel things? What things? Are you intentionally writing about moral ambiguity and the blurred line between good and evil? Is that a theme of your writing? Does it fit with the rest of the story?
If you knew the answers to those questions, you'd have a much better idea of how to execute your goal. It's important to have clear, specific goals (such as, "I want my villain to be sympathetic because that helps achieve my theme of exploring the roots of evil and how society consistently fails to get ahead of these repetitive problems because we sympathize with certain types of criminals and even sensationalize/glorify them"), not only general goals (like "I want people to relate to my villain"). Knowing your very specific goals will inform the how of your execution.
Oftentimes, you don't get to these specific goals except through multiple drafts! Keep writing and discovering your story!
Source: reddit post