Class today went okay, but having the second pair of eyes, my observer, offers me some lessons that I can use long term.
Never promise to let students out early. It will piss them off if you fail to do so. It will also prevent the students from getting into whatever the class is doing that day. Don't apologize for keeping students around, unless they need to. Previous line of thought: I believed, and I still do a bit, that one can't force the students to do work they don't want to do. But they'll do the work and learn if they don't realize they could be half-assing it. So, use classroom authority to make students do what's good for them.
Do the "duh" explanations before class, and plan them out. General misunderstanding is too easy to let happen. I had some confused students in class today; I wanted them to write their thesis statements down, but I did not differentiate whether to write their thesis statements or the person's they were peer reviewing. Write things out. Like on this blog.