"I might be an outlier in how I learn, but I find that learning happens in multiple passes."I don't think so, I'd reckon you'd be pretty typical. It's basically how I learn things and I'd think it's how most others acquire skills.
From my experience, the key issue is having an interest in the subject, subjects that I was interested in I did well in and it was the opposite for those that bored me. I suppose that makes sense but in both cases multiple passes were required before I became proficient - it's just that it took considerably longer when my interest was less.
However, what I've noted on many occasions is that there are students who I'd classify as a class that are just good at learning things even if the subjects have little interest for them per se, they're the ones who would often top the class and later in life you'd find them doing jobs unrelated to the subjects they did well in. I often think I'd like more of that trait.
For reasons I can only speculate about, my interest in certain specific subjects seems to have inate origins, it's as if some a priori interest was there before I knew about them. This doesn't necessarily bode well for other subjects that are deemed essential for one to become skilled in as one's learning can become lopsided.
There's little doubt that hands-on training works for most - and that brings me back to clocks. In physics practical classes on tension, springs, mechanical advantage, etc. we actually had clocks to experiment with. These were usually old bedroom alarm clocks and such that could be pulled apart and reassembled and if damaged it didn't matter much. We all learned from these experiences, even kids with little mechanical aptitude as clocks contains just about every instance of the physics we were learning about and it was obvious how they all came together to make clocks work.