I treat CLI tools like tiny products. The faster someone gets to a win, the more likely they are to keep it around.
Habit 1: default to a useful output
If a command does nothing without flags, it feels broken. Give a helpful default and a short hint on what to do next.
Habit 2: make errors human
A short actionable message beats a stack trace every time.
Habit 3: document what you learned
Every release gets a tiny note. This doubles as a reminder for future you.