Just as I consider doing a bit of my nascent mindfulness practice before going to teach, I see that PhD Comics has its own commentary on the need for mental preparation before teaching. The sad thing is, abandoning hope isn't all that far off from my goals before setting out to teach, mindfulness or no.
The aim is to be in a state where I am no longer personally attached to whether my students enjoy my class, whether they participate or fall asleep, whether I sound like a knowledgable professional or can't avoid saying "uh" and "um" every few sentences. You might say that I'm just getting rid of the stress that makes "what if I do a bad job?" a self-fulfilling prophecy; or you might say I'm abandoning all hope that the class will go well. It's all a matter of perspective.