What makes a good main essay? How do I make it different from all the other ones out there?

Write it in your own voice and let your personality shine through! You want to be professional-ish and of course polite, but don’t feel that you need to be stiff and dull. Write something fun to read and true to who you really are–the you that your friends know and love. IMHO, when you write about something you love, you sound the most like your true self.