Long ago, I was an art teacher. I was also the pottery teacher, but I've never been good at throwing. It was like "Wow that's... better than anthing I can do! Okay!"
My first session, which was a short visit of a couple weeks, went pretty well. I made one, I feel, major mistake during my second session, which was a whole semester split between two schools. My mistake was following the lead of the real teacher and being a disciplinarian. Hardcore. I punished bad students, albiet half-heartedly. I think the students could sense I wasn't really feeling as strict as I acted, and it was not exactly smooth going.
Then I got to the junior high and leared that 1)most rules are arbitrary and should be ignored 2)ultimatums are a stupid thing to utter, cause if you follow through half you class could end up in detention that period, or you could just undermine your own athority if you don't follow through (for this reason don't be a disciplinarian in the first place, you have to follow through from then on) 3)Special ed students love you; regular students hate their lives and project that on to you.
So, I feel I am a much better teacher these days. I don't discipline; it's actually a very interesting experiment, this Japanese Education system. I don't really reward either, beyond a "your team won!" There is some guy I learned about in pedagogy classes that advocated this system. Basically, students will learn if they want to, and that is what happens here.
Also along nostalgic lines, today on my "radio show" I will teach the students how to use "in'it", just like my Native American students used to do.