Order is Important on Day 1!
I have found that when I have forgotten or been a bit flustered and changed the order in which I began class on the first day, it does not run as smoothly as it would have. Also, I don't get as much feedback from students. This is a simple thing, but very key in starting out with your students on a good foot!
In the past I have found students pick up on fluster/disorganization very quickly & run with it. Really fast. Depending on the age group, its hard to get them back.
I have an outline of the information I want to convey in the order I want to deliver it to help me stay on track and ensure I cover all the bases.