Good questions. Supplementals are aimed at making sure you really like their school and are familiar with it. Start with the big things that you like about the school, rather than things like “I live just a mile away.” What is the FEEL of the school? What do they value? What makes them your favorite? Prove to them that you are itching to go there. In order to do this, you will need to do your research on what is different about that school. They don’t expect you to know everything about it, but you darn well better know some things that separate them from other schools.