Being Ready
You have to plan ahead, however don't drive yourself nuts. Know your subject, plan for problems and be capable of changing course at time.
As part of planning ahead consider different scenarios that may develop and how you will address those and then get back on track in a reasonable amount of time.
I agree, if your not prepared, then the students will not follow thru on their assignments.
I could not agree more with being flexible. Knowing the subject matter is 50% of the presentation.
T. King
If your not ready for the course content, your students will eventually realize that your understanding of the content is flawed. A couple of classes like that and you lose respect from your students.
I am in total agreement with your statement...Living up to your syllabus is a must.