You cannot direct a system you have not watched.
Observe the flow before you direct it. It's the closest thing I have to a rule, and it came from watching rather than from a book.
Every system already has a current running through it before you arrive. A team has one. An incident has one. So does a budget cycle, an agency, a market, and any room full of people about to decide something. That current is there whether or not you've bothered to read it, and the fastest way to lose is to push against a flow you never took the time to see.
Most of the expensive mistakes I have watched, and a few I have made myself, came from someone deciding before they understood. Usually because deciding felt like leadership and watching felt like hesitation. It's almost always the other way around. The watching is the work, and directing is just what becomes possible after.
The technology was never the constraint.
Every security program I've run came down to whether the people in it were all right, and none of it was ever mine alone. A team that has been looked after holds together when something is genuinely on fire. A team that has not been comes apart at the exact moment you need it, and no amount of tooling closes that gap.
I mentor on purpose.
Mentorship that never gets scheduled is mentorship that never happens. Somebody did this for me at a point when I couldn't see the path from where I was standing, and a debt like that doesn't clear itself.
Depth is not optional at the top.
The higher the seat, the more expensive it becomes to be wrong about the technology. I still read the standards, and the code I write for myself is out in the open on GitHub. Mostly PowerShell, mostly small tools for problems I actually had. Keeping my hands in it is what lets me defend a strategic call when somebody who knows the material pushes back.