I am reading Mortimer Adler ‘How to read a book’, and it is really brilliant! It discusses techniques of reading, and the educational system in general. Much of it can be applied to language learning and it is even mentioned a few times (simply reading through a foreign book for overall comprehension, not getting bogged down in analysing everything).
As a final note, I really dislike this new wave of books about ‘how to be productive and rich in 3 hours doing nothing’, so it was refreshing to find a book actually helpful in building skills, and it is wonderfully written since it is quite an old book so uses that elegant old style.
If you enjoy older books like that about reading and learning, there is another often overlooked gem I can recommend called “La Vie Intellectuelle; Son Esprit, Ses Conditions, Ses Méthodes” by Sertillanges.
Its catered more for those in academia, but much of the content applies to learning and work in general.
Hello! I read this summary article before reading the book, and found it very helpful. Reading the book itself the best option, but this article is a good start :))