From a young age, JFK was interested in politics. And to help him learn complicated policies, he would stand in front of his bathroom mirror and recite the intricacies of various policies aloud. This practice helped him not only with subject retention but also with confidence in his ability to speak on various issues. JFK is known as one of the best public speakers in U.S. history and it all started with bathroom recitals.
Physicist and polymath Richard Feyman often claimed that the test of true subject mastery is if a person can effectively teach complex material to an 8 year old. See an example of him illustrating this practice here .
I discussed a variety of work-related topics with a client earlier today and then did an interview this evening about running. I got through them both but I can do better. Given examples above, next time I speak about an idea with people outside of my personal network, I will layer in verbal prep in addition to note taking.