In this thread, I will share with you my 30 some years of experience in studying English, started in the late 70s, as a high school student in one of the poorest towns in China, continued in Tsinghua and Cambridge, and then as a professor in the United States teaching my Chinese postgraduate students English, and finally as a parent watching my two kids growing up into their college and high school years.
One word of wisdom for all learners: however good your English sounds like, however well you write, if you cannot think in English and cannot use the simplest few words to express your idea, then you have not learned English yet. Next time when you speak, pay attention if you can correctly use the few words like she he her him, do did does, has have.