Since you can easily overlook details on the first reading, read the assignment sheet a second time. As
You need to fully read the assignment and not just start writing on the prompt. You will return several times to the requirements. Either print the assignment requirements or have them pulled up while you are brainstorming. You will save yourself a lot of time
When it comes to choosing an audience, don't consider it writing to your instructor. Your audience can be someone you are trying to teach the subject to, or a piece for a future book you are writing. If you are just writing because your teacher assigned you are not understanding the assignment.
It is important to ask for help no matter what level of learning you are starting as a freshman, or a returning student. The world changes so much and you never know where the next big idea may come from.