Here’s a podcast I did on the science of learning, and how we can improve our tactics regarding learning.
I draw largely on what it is the very best book on the science of learning:

Make It Stick: The Science of Successful Learning by Peter C. Brown, Henry L. Roediger III and Mark A. McDaniel
It is brilliant from start to finish: a clear and comprehensive explanation of the science of learning, applied to actual humans trying to learn stuff and longing to make that stuff stick – this book tells you almost **all** you need to know (it doesn’t focus on sleep and memory, really – which I discuss it more detail here).