Below are some of the documentation practices that I came across.

• Create documentation as you design and implement something new in the environment.
• From Owen’s mycugc post, Check if you pass Bus Test.
• When you write a script add a help section explaining what it does. Similarly, when you implement a scheduled task, update the description with what it does.
• When you create service accounts, in the description, always explain why that account is created, where is its password saved (like keepass etc). If you know what the account is used for, and don’t know the password, you cant use the same service account when that infrastructure server is recreated. You can’t just simply delete that account as it could be used anywhere in some other server.