One thing she did not specifically talk about, but is implied in any well-planned lesson, is to have a Plan B. I've discovered that there are lots of unpredictable parameters, that you really REALLY need to make sure you have contingency plans. You need a Plan B. Sometimes a Plan C, and maybe even a Plan D.
In my first year of teaching full-time, I struggled to stay one lesson ahead of my students. Sometimes that was a stretch, and on more than one occasion, I would discover either upon arriving at school, or in the classroom, that the new worksheet that I had just finished putting together for that day's lesson was still at home...sitting on the printer. Fortunately, I had brought other materials, including my collection of sentence strips, so we could practice dialogues, and I was able to manage that day's lesson in spite of the change in plan.
Another important contingency that I've learned to keep in mind is the fickleness of technology. I've prepared entire lessons based on showing a video from the Internet...only to have the Internet go down at the beginning of class. One time I set up my computer to project a lesson from the classroom where i was teaching (not my own), only to find out that there was no power to any of the outlets in that room. That's why it's so important to still have hardcopy of things. It's great when you can use a combination of technologies, and project an activity onto the interactive whiteboard. However, in case something goes awry and you're not able to do the lesson as planned...you definitely need to have an alternative in mind.
Last week, I ended up using Plan C for a particular lesson. I was going to teach a "Classroom Rules" song from a the CD/Book set "Let's Sing Mandarin" to my Kindergarten students. I had somehow gotten a scratch on the CD and one of the songs (not the Classroom Rules Song, fortunately) was unplayable in the CD player. One of my colleagues suggested that I rip the CD to my computer, and that I should be able to play the CD without skips afterward. It turns out she was right! Anyhow, I decided that, instead of using the CD player, I could play the Classroom Rules song directly from my computer (which I've successfully done for several classes now)!
When I teach the Classroom Rules song, I do it with actions and movement. The first action is to sit properly, (坐好, zuo4 hao3) so I try to demonstrate what sitting properly looks like. I decided that it would be better to demonstrate by actually sitting in a chair so my students would be able to imitate my actions. I tried to roll my desk chair out from behind my desk to the front of the classroom. In the process, I accidentally bumped the power cords connecting to my computer, and disconnected the computer. I decided that it would take too long to power up my computer and log in again, so I decided to try Plan B: playing the CD in the CD player as before. The power cord was unplugged, so I plugged it back in...not realizing that I plugged it into the wrong place, so I couldn't figure out why there was no power to the CD Player. The students were waiting for me to do something, so I ended up resorting to just singing the song myself. We went through the three rules (坐好, zuo4 hao3) meaning to sit properly, (安靜, an1 jing4), meaning to be quiet, and ( 舉手, ju3 shou3), to raise one's hand. While I prefer to teach the song with the CD, I was able to manage without the CD or any recorded music.
While the vast majority of classes go according to plan...I've learned from the Scouts: "Be Prepared." And I have learned always to have a Plan B. Contingency planning is my friend.