Be kind and lead by context. Is surprising how many managers think that their job is being the dictator in charge, and how often they treat their teams as children.
Your job as a manager is to remove blockers, provide context and make sure your team is working effectively.
Not a manager, but as someone who had a REALLY political manager who tried to undermine everyone around him, including (and especially) his subordinates, The 48 Laws of Power by Robert Greene taught me how to cover my ass and how to generally be effective in an org.
I was an engineering manager for about a decade before I quit and went back to being a developer. I hesitate to give specific advice, since I don't think I was very good at it. But here are some things that, looking back, were sources of difficulty:
- You can do some amount of development work, but don't put yourself on the critical path for your group's work, or you won't have time to do the important things that only a manager can do. (Or you'll try to do everything at once, and burn out.)
- Don't be too friendly with the people who report to you. It's hard enough to lay off an employee, but having to decide which of your friends to lay off is much harder. You also don't want to be in the position of telling your friend that their work needs to improve, etc. (Similarly, don't be surprised if the people who report to you don't want to be your drinking buddies.)
I am a startup founder managing a team of 3 developers and 2 sales persons, I can say from my personal experience that team building and culture are the most important points a new manager can focus on.
1. Team building: you should ensure your team share a vision, are aligned around the same goals, and each one of them is a accountable for one specific subject she/he is good at.
2. Team culture: try to naturally build a cult like culture for your team, by that I mean some kind of special rituals or habits that differentiate you from other teams or groups. This will strengthen the bonds between team members and improve productivity long term.
1, CYA it's sad that I have to say that, but yes, cover your ass, politics plays a big part in jobs and (good) managers generally shield you from the pressure so until you're in that position you've no idea how bad it can be
2, don't be too friendly with the people reporting to you, they won't take you seriously as a manager and will happily go over your head
3, encourage personal growth of your team and be there for them as a mentor and friend (which contradicts 2, there's a balance to get)
I have heard managers described as a "shit umbrella" for their team, I'm pretty sure now that that's true, especially for good managers. Know when to keep your team out of things they don't need to worry about or be involved in and in general I think they'll be happier for it.
The Little Book of Psychology will give you the lay of the land. Then build up your library over time as you deal with specific issues.
The key is awareness of the important concepts of the field.
Most managers have very little awareness of the field. And under time and resource pressure, come up with their own half baked theories and solutions which seed further issues and compound misunderstanding.
Your job as a manager is to remove blockers, provide context and make sure your team is working effectively.