What you absolutely need as a desideratum is a lot of beautiful and elegant experience in the lessons given by your instructor, Toshiyuki Namai.
Human life is transient more than you ignorantly imagine. The most effective way to stoically learn and master elegant English is that you substantially have much time to experience of the "beauty" and "elegance" through stoically receiving so many intellectual pieces given by your instructor.
In particular, experiencing "exquisite beauty" (the utmost state of beauty) through receiving lessons in English spoken by him at Ginza Sanctuary authentically engenders a golden opportunity for you to be more sophisticated aesthetically.
On the other hand, just having general knowledge doesn't give you any opportunity for you to be more sophisticated at all.
It is not a beautiful and reasonable idea to obtain many pieces of knowledge in order to just satisfy greed for knowledge. Greedy greed is really ugly. Evidently, there is nothing beautiful in it.
It goes without saying that you are systematically guided to be more beautiful and elegant by inches in the lessons given by your instructor. What you simply need is to follow all the teachings given by him.