Generally, I try to prepare the material with the mindset of: “If I was a complete beginner or user to the system, what would I want to know and what should I need to know?”
Of course, if you’re not careful you could run into a rabbit hole where you’re putting in too much information or explanation in the documentation which could extensively lengthen it.
I have seen cases where documentation has been written with the assumption that the user has some other documentation. I think in such instances it is very helpful to include your assumptions at the start of your documentation.
What do you keep in mind when writing good documentation? Drop your tips in the thread