Elizabeth,
I feel so off when the plan I have in my mind for the day is not ready by the time class begins. Actually, I like to arrive at least 30 minutes early, and even before that, I want to be sure everything I'll need is ready. That 30 minutes I commit to student attention as needed, answering questions, or just just chatting to connect and reinforce positive relationships. Students are more relaxed when they sense their instructor is relaxed and ready also.
Barry Westling