I have actually done the 4 first books on the YDKJS, I'm now at "Async & Performance".
Most of the concept have been pretty clear to me and helped me really understand JS better. What I will need to work again is all the little details when I will be applying them for the projects.
People here would find a good use at Anki : https://apps.ankiweb.net
Write in these flashcards the most importants concepts and mechanisms about each chapter. With that, you will not forget them, and then by applying them consciously when you code, it will stay in your long term memory.
I do one or two chapter a day. I have a lot of free time so don't relate to me. But indeed, it sometimes get boring when you keep making flashcards and reading for weeks. Don't give up
PS : if you're looking for some background music to put you in the coder zone, check all the Spacemind mix : https://www.youtube.com/watch?v=uL0mvPZuklM