What is the best way to learn English

The first answer is: Nobody knows. And the second answer is that because nobody knows the best way to learn English, there isn't one. It's an old fantasy for learners and for teachers - to find the one perfect key. So many teachers, English language schools, universities, academics, business people, etc., say that they know the best way to learn languages, but that's only to make money. Don't believe them.
At Severnvale our experience has taught us that there are three simple conditions for good progress:
You must be positive about learning English. It doesn't matter why you're positive - because you enjoy language, or because you hope to get a better job - but you must feel enthusiastic about it.
You must feel relaxed, comfortable and secure - not only in the classroom, but outside it too
You must accept that quantity matters as much as quality - in other words don't waste too much time worrying about the best way to learn English when you can spend time reading, writing, talking or listening to English instead! Doing a lot of language is better than doing one little bit perfectly.
(And something else we've learned is that it's possible to make some progress even if none of those conditions are right!)
But one thing that all teachers and academics agree about is that people are different - different people learn better in different ways. So the really important factor is to find the best way for you to learn English.