I think two very important components of the first day of class are creating a positive first impression and setting clear expectations. The impression students have for you on day one is going to stick throughout the entire course. If you are unprepared, they are going to expect this will be the case each time. Also, the expectations you set will carry on for the entire class. Make sure you know what you expect from students and tell them clearly so there will be no surprises in the future.
