I think you need at least 10 messages to PM with folks. A good place to start with your essay is your high school english instructor. (1) They should know you at some level (2) They will provide input to USNA on your writing skills anyway (this could help them understand the application process).
The essay should be about you and your aspirations. It doesn't have to be flowery or display gung ho type zeal. I personally don't think it carries much wait unless (a) it is pitiful (b) you are on the margins. I am not discounting it or suggesting you not put effort into it - just that I don't believe it is make or break and certainly doesn't need to be worthy of a pulitzer type prize.