This has been a fascinating thread, and has given me several good ways of articulating what little I can claim to know to others I might now find myself in a position of trying to give a little bit of mentoring to. I was fortunate being in the reserve that even an as officer cadet I was thrown almost directly into the breech without any formal training, with a number of excellent senior NCOs to guide me.
One thing that sticks with me actually was something Journeyman told me when he was my OC years ago - well - more something he told all the officers - "you must be seen to be seen to be leading". That said, I was generally pulled back by NCOs if I ever got too stuck in to a task where I was not needed, and that was important to start learning the role I was supposed to be playing. I found this worked well, because when I leveraged the NCO's skills instead of trying to direct everything I generally got far better results, and that seems to be the experience of other posters, and generally of any sort of leadership, including what I see in my civilian work experience.
I've now come to a new unit as a platoon commander, and not knowing anyone am now realizing why it's so important to leverage NCO's knowledge of the troops and the unit - to make sure that we're using the skills of everyone as much as possible. I've always taken that Napoleonic view as well about the field marshal's baton in every rucksack and I believe it's important to harness the skills in all of them, especially the leadership potential. I'm trying to spot who future section commanders, and future officers are where I can just by trying to watch interactions, and developing the same sort of "prospecting" in them is important too.
Definitely have to remember the "drain the swamp" analogy, that's good....