Rationality was an incredibly beneficial book for me. It was a bit of a slog to get through, but absolutely worth it. My cognition has improved, and I came away with a stronger mindset for learning and reasoning. The book itself is engaging and polarized; Eliezer Yudkowsky writes with an unapologetic style that can be irritating, educational, dramatic, and intuitive all at once.
My strongest technique for increasing retention from lecture. Maybe it’s obvious; when I decided to make the mindset shift, it wasn’t so obvious, but the results are outsize.