Hi Elizabeth:
I agree. When students begin to appear on the first day of a new class, first impression can make a big difference. So when they see the instructor is present, waiting and prepared when class begins with a thorough plan for the day, resources gathered and ready to go, along with an enthusiastic attitude, that's going to convey important expectations for how the class is going to be conducted.
Also, being approachable, friendly and patient, tolerent, and willing to offer encouragement and support at the outset, these traits state the teacher cares about their students and their success in the class.
Regards, Barry