Step 1: pull your 10 highest-engagement posts from the last 6 months. Sort by saves + comments, not likes.
Step 2: read them out loud. Mark the patterns: do you start with a number? A confession? A question? Do you use short sentences? Lists? Em-dashes?
Step 3: capture five things, tone keywords (3 5), sentence style (short/medium/long), vocabulary level (plain/technical), signature phrases (2 4 you reuse), and persuasion style (story/data/contrarian).
Step 4: feed those five into your AI tool's voice profile. Test by generating a post on a topic you've never written about. If it sounds like you, the profile works. If it sounds generic, your inputs were too vague, go back and get more specific.
The whole exercise takes 30 minutes. It's the highest-leverage 30 minutes you'll spend on AI-assisted content.