How To Learn English

If you want to learn a language, you need to get used to it ←　I think so.

many English classes in Japan ask you to memorize dictionary definitions or Japanese translations and do not encourage you to get used to words in the manner that I have described above. I believe that this is one of the most serious problems with English education in Japan today.
That's true!
When I was a high school student, My English teacher told us same things.　While I'd been to Australia I thought that "I dont know how can I say... my English doesn't work...though I've studied English since I was a junior high school student.. It's nosense!"
I think Japanese too much worry about form and grammar at the first stage.
英単語力があれば良いに越したことはないですが、普段の日常生活の中で使うほとんどの言葉は決まり文句で、文全体が一セットになっています。だから、don't worry を do/not/worry と分ける必要はないのです。don't worry で一つの言葉、音の流れで覚えればいいと思います。
私たちが日本語を覚えたように、普段から使わないとそう簡単には身に付かないのかもしれません。だから続けることが大事なのかもしれませんが、それ以前にあまり難しく考える必要はなく、文章でも音楽でもいいし身近なところから英語に触れ、楽しむことが一番だと思います。

overemphasize：～を過度に強調する Grammar is often overemphasized.
sufficient：十分な、足りる $100 will be sufficient for your trip. /Add just sufficient milk.
fairly：公正に、公平に fairly priced goods / be fairly treated
gradually: だんだんと、次第に The storm has gradually abated.