How do you write to fulfill the academic requirements at university?

I want to explore how do you write as a graduate student or how you were used to write in your PhD student life. Graduate students who are reading my blog, please help me to understand your writing problems. Do you brainstorm first or do you plan first on which topic  are you going to write  or do you simply follow the guidelines by research papers or guidelines from graduate schools. I appreciate your reply to these questions.