If You Had 15 Days to Learn Calculus, How Would You Do It?
"...the most effective method is intensive practice combined with trying to form deep intuitions about the principles involved, then this matters a great deal. Because this is also the foundation you can learn anything from"
Scott Young - YouTube
Optional Interview with Scott Young, a "Marco Polo" of Learning - University of California, San Diego | Coursera
One Simple Method to Learn Any Language | Scott Young & Vat Jaiswal | TEDxEastsidePrep - YouTube
He also traveled with a friend in 4 countries for 3 months each, to learn language.
Apparently that worked well also, since they used immersive, "no English" learning.