As a first-time developer promoted to manager 3 years ago, of a small team, IMO this is good advice and well written. I would add about trusting your team members and delegation, well, you get to learn what everyone can accomplish, identify weaknesses and couch when needed, but it's not instant magic. So not everything is always on track. Add that some of us have to manage and still deliver code (by choice or not) and you have the common sense and advice saying you can't do both, but need to keep up coaching, helping when things go wrong, etc.

So it's not just about following advice, real world hits just as in development estimations...