Hi, Yiyi. If you want to improve your English, I would suggest find a teacher and one or more language partners. With the teacher, you can have as many classes as you need and can pay for, and language partners are here to help you on daily bases, for free. I would recommend practicing your English everyday with one or more language partners, as well as writing Notebooks here on italki, so someone can correct it and explain your mistakes to you. Also, from my personal experience, I can tell you that listening to music, watching movies with subtitles, reading simple texts and highlighting the unknown words most certainly help.