Do the instructions offer guidance? Last year it said this in regards to the Biographical Essay, "You must include your reasons for wishing to attend the Academy, a discussion of your curriculum preference, the development of your career interest as a result of your high school classes, hobbies and activities, including any sailing experience, seaman’s experience, and/or military experience. You must also state your understanding and willingness to accept the service obligation upon graduation."
Good luck to you.