Start from your first-week tickets
Pull the questions from tickets in a customer's first seven days. Ignore what you think they should ask.
Keep it to ten questions or fewer
A long FAQ is a help center. Pick the questions that block people from getting started.
Answer in the first sentence
Put the answer first and the detail after. Link to the full article when there is one.
Put it where new customers will see it
Link it from the welcome email, the first screen and the contact form.
Review it every quarter
Check which questions still arrive as tickets. Replace the ones that no longer matter and fix the answers that did not work.