I finished the English course
From among courses in Duolingo, I finished first - English course in Polish language. Now I know better English, tomorrow I will start to read English novels. Now I learn German and Swedish - I have many time to use, so I can learn many languages (not only in Duolingo - I have also books and movies in different languages).
I didn't use this metod. The Emil Krebs method is a cheap marketing trick - many courses offer to know a languge in ten days. A good knowledge english on level A2 appers to twenty days (the Emil Krebs method offers 10 days on B1...). Otherwise, this method didn't elaborate Krebs - Krebs learned any language by three months, learning a few hours daily. Krebs swoted many words and phrases - without none a good method (otherwise, this method was perfected from fourty years, and Krebs died in 1930). During the learning, I have read many english news, I have translated in my mind polish sings to english, I have read articles in Wikipedia.