You start using corporate jargon. You become more authoritarian. You embrace careerism (a term I invented to describe people who erroneously conflate rising in corporate rank with happiness). You quickly learn that no one understands anything about the people or the business--and that all decisions are made by gut, cherry picked data, and story-telling. Suddenly, you'll be afraid to disagree.
Your only job as a manager is to protect and develop the team under you. You must actually like people and have a fundamentally benevolent worldview. You must be willing to say "I don't know" 10x more than as an IC. You must believe deep down in your core that ordering a human being to do something is a sign you must introspect about your failure as a manager, and commit to fixing the problem.
You must be prepared to tell your own manager to go kick rocks. Ambiguous situations are one thing, but you must never, ever knowingly do the the wrong thing. Everyone will know when you do it, and that will be the beginning of the end of your own happiness.
All other approaches will lead to you failing to deliver results, failing to retain, and a drag on the org.
The error I have seen most engineers-turn-manager make is they had a deep dissatisfaction with other terrible managers, so now its their chance to make the right decisions and do things their way.