Grab the PDF! --- I'm very interested in learning, partly because learning = growth = happiness and fulfilment, and partly because being able to learn quickly is the only way that one can remain truly safe in any era.
Since this is such an important skill, it should pay to know how to improve our efficiency at the task. So how do people learn?
I am fully in support of the "learning by doing" methodology. However, I do think that there's this early stage whereby not much actual "doing" seems to be happening, but in fact, the mind is hard at work.
It's at this beginner stage that the conceptual understanding of knowledge happens.
This, I think, is also why mentors have the opportunity to be either really helpful, really useless, or really harmful.
A great mentor gets you over this conceptual hump as quickly as possible, the price being the intensity of study.
A useless mentor doesn't affect this pace at all, and you progress at your natural rate of self-learning.
A harmful mentor gives you the wrong conceptual understanding, leaving you with the illusion of learning, only to wisen up years later having to undo the harm that has been done.
Programmers and mathematicians are known to be notorious autodidacts, so we know that can work, even for advanced disciplines. But if you really want to get up to speed with some area of study quickly, a good mentor is by far the quickest way.
Then again, not everyone wants or needs to learn things quickly, and learning things by yourself is a wonderful gift.
Whatever your path is, there are various ways to succeed, so long as you avoid the perils of bad mentoring.
Put more succinctly, treasure a great mentor, be bold about self-learning, don't attend college lectures.