Hello everyone, I'm a Chinese student who wants to be an exchange student in America or England, but the English study is so difficult for me....

In order to improve my English skills(or abilities?), I spare no efforts to study English by various methods, such as self-learning and learning with tutors. However, while I could get a comparatively good grades(compared with myself in the past), videos on Youtube is still difficult to me.

Em...Here are some of my questions:
a) How to memorise words? .... Although wordlists enable me to have a look at a wide range of words, it's really difficult for me to use them both in writing and speaking.
b) How to speak fluently?.... amount of speaking exercise only?
c) How to write a well-organized passage?....

Question A troubles me most.\\

(´°̥̥̥̥̥̥̥̥ω°̥̥̥̥̥̥̥̥｀) Could you help me?