The most important thing when creating a community policy is to ensure fairness and transparency. Clearly outline the rules, enforce them consistently, and make sure the consequences are proportionate to the violations. Also, provide an appeal process so users can challenge decisions if needed.
The most important thing I think:
When a post is deleted by moderator, explain to the poster why it was deleted.
↑This will also help reduce inquiries from users.
Other candidate 1:
Show examples of posts that will be restricted in policy.
Other candidate 2:
As a general rule, delete content using human moderators rather than AI (however, delete criminal data automatically using e.g. Amazon Rekognition).
Hope it helps :)