Wyner, an opera singer turned language acquisition geek, describes his method for acquiring new languages, arrived at by years of trial-and-error and perfected to suit the language acquisition needs of the trade and using modern tools.
This is one of the more balanced and reasonable books on this topic. Wyner explains the challenges involved in acquiring a language, veering not far off from the science and the experience of many language learners including himself. The method he describes relies heavily on memorising words using Anki (a free flashcard / spaced-repetition package), augmented with other tricks for the various skills required to master a language. Special attention is given to pronunciation, a topic too often missing from other books.