There's no doubt that Richard Feynman - Nobel-winning physicist, solver of the Challenger disaster, and above-average bongo player - was a brilliant mind. In addition to many insights into the fundamental workings of the universe, he gifted us mere mortals with a handy guide to learning that is worth repeating:
1) Write the name of the topic on the top of a blank page.
2) Explain the topic using simple language, as if to someone with no prior experience.
3) Examine your work for any assumptions, lack of clarity, or places where you simply paraphrased another source. Go back to the books if necessary.
4) Simplify, shorten, and substitute metaphors at difficult places. Repeat.
The end goal of this process is to achieve a mastery of the subject. And a handy side effect of having an understanding of a topic with this particular technique is that you're perfectly positioned to explain it to audiences who have no prior experience using simple, uncomplicated language with lots of metaphors.
As a bonus, it's iterative. It's a template for continual improvement in understanding, allowing your knowledge to deepen the more times you repeat it.
Of course this is no easy feat. A brief 10 minute presentation on a subject could take hours upon hours to prepare. But when the presentation is over you at least have a decent shot of claiming to sincerely understand the material. And how often do we get to say that?