The first days of class are important. This is the time to interest your students and grab their attention. Make class expectations clear, make the content clear and fun as well. Express to them the importance of a supportive classroom environment and encourage them to move forward by making the class fun and interactive. Some students will come to orientation and even the first day of classes but sometimes won't return after that, so make the time that you have with them count. They might come back at a later date when they're ready.
