[soramimo]

I recommend the book "How to read a book" on the very subject (summary in [1]).

In a nutshell the author argues that the goal of reading is to increase one's understanding. For this the writer needs to have a better understanding than the reader. The reader must be able to overcome that inequality in understanding to some degree.

A critical first step is deciding whether the book deserves a detailed reading in the first place. Clearly, this is critical for time efficiency.

Once deemed worthwhile, you can move on to a thorough analytical reading where I think note taking trumps speed. The process of actively reading the book will help digest the author's main points and help you remember them.

Finally, if you're trying to grow your expertise in a particular area, consider reading and contrasting multiple books on the subject (comparative reading).

[1] https://lifeclub.org/books/how-to-read-a-book-mortimer-j-adl...