Personally, one of the most difficult aspects of preparing to teach is taking on the responsibility and authority inherent in lecturing/grading 20-40 students. Like Alex said, it is difficult for me to think of myself as a teacher. I found Boice's "active waiting" helpful in this respect because it provides a way to slowly immerse myself in the practice of teaching. Instead of the rather daunting task of sitting down and writing a course plan all at once, I can jot down ideas throughout the year that will slowly take the shape of a course plan. Also, I will get in the habit of "thinking like a teacher," so that next year I (hopefully) will not be surprised by problems that may arise. I will have thought ahead and prepared for the inevitable concerns - "What if an assignment proves too difficult for certain students?" "How can I keep students engaged in the more technical or formal aspects of writing?" "How will I design the actual, day-to-day classroom discussions?" Starting to actively wait this early has two benefits - it reduces stress by elongating the process of course design, and aids in preparation by providing a process. Even if the process may seem scattershot at first, I think over the course of a year the bits and pieces will add up to a much more effective course.