Do not let school interfere with your education. Formal education is important, but you do not need a college degree in English to write well. And, in my opinion, the intensity of useful education diminishes and the amount of political indoctrination increases as one advances through each grade level. Study because you are passionate about a topic, not because you are trying to achieve a better grade point average. Question every assertion until you have evaluated the facts to your own satisfaction. Do not believe just because others believe. Believe because you know it is true.
You may have noticed that I did not include such mundane advice as study English grammar or write every day or read the great books of the western world or write about what you know or keep a personal journal. Better authors have already covered these suggestions. My goal is to push you beyond the mechanics of writing to explore the deepest regions of personal expression. But a word of warning: when you finish, you may decide to become a jazz musician instead.