WHO vs WHOM

Do you ever struggle with the WHO versus WHOM issue? Even when I thought I knew, I questioned it. Being both a writer and an editor (meaning others depend on me to understand these things), I was responsible to be clear on this matter. There was no room for guessing. Since I often got confused, I thought it would be something to share.
To begin, we need to understand what a pronoun is because that will determine if we use WHO or WHOM. In the simplest terms, a pronounce is a short word used to replace a noun, which is a person, place, or thing. That means instead of the teacher, we’d say he or she. Another example would be replacing the book with it.
The reason pronouns matter is because WHO is used when referring to a SUBJECT pronoun while WHOM is used for OBJECT pronouns. Now, that might sound complicated, so let’s break it down… If the pronoun comes BEFORE the verb, it is a SUBJECT pronoun. If it comes AFTER the verb, it’s an OBJECT pronoun. Another way to think about it is this, if the action is HAPPENING TO the pronoun (used as the direct subject), it is a SUBJECT pronoun, and you use WHO. If not, then it is an OBJECT pronoun, and you select WHOM.
Here’s a great table from owl.purdue.edu to help you with a visual:

I hope this helped or at least offered you some resources to aid in your understanding.
I don’t care about grammatical rules. My own rule is never to use ‘whom’ – none of my characters would use it because they are all ordinary people, and ordinary people don’t speak like that 🙂
Colloquialisms do need to be considered, but this in more in context of narration opposed to dialogue. Of course, that also depends on the style of writing you are doing, as well. LOL
Very helpful, thank you.
Thank you <3