I am now studying German with a grammar book by Sekiguchi Tsugio. He says in this book that English is one of those languages which you can learn not so much by studying it as by getting used to it. So, he continues, when you want to master English, it is advisable for you to practice unceasingly. On the other hand, according to him, when it comes to learning German, studying and memorizing is of greater value than mere habituation. This dichotomy of languages, namely classification of them according to what you should do when learning them, impressed me as useful when teaching English. I agree with him. Habituation plays the principal part of learning English. But how you get habituated is the most important part of it, for, in my opinion, no matter how familiar you get with English, there are sentences or expressions which you don't quite understand at the first glance. This feeling of incomplete understanding you must make much of. This is because you have to make the full sense out of it by looking them up in the dictionary or consulting a grammar book in order to take your habituation to the next level. I observe many people who have gotten habituated to English to a certain degree ignore this feeling and trust their understanding, only to have and get content with a poor understanding of them.