I once heard that the ideal model for learning something should follow a basic "hear it, see it, do it" format. In other words, hear a verbal explanation, watch it being done (probably several times) and then do it yourself (definitely several times).
In my own experience teaching, I've spent a lot of time thinking about the first step. Here's a few things I've come to realize about this stage over the years, both from my own experience, and also by observing the many wonderful teachers I've had the opportunity to learn from.
1) Keep it short.
I'm constantly trying to find the best way to describe to people what's going on in the most succinct way possible, while at the same time trying to avoid getting too verbose and veering off onto tangents. The less time I talk, the more time we all have to practice, and that's the important thing. Again, I'm of the Elvis mindset: "A little less conversation, a lot more action".
2) Repeat it three times.
I'm also a firm believer in repeating things. And from what's I've heard and experienced, 3 tends to be a magic number when trying to ingrain something into another person's memory. But here's the trick: it's not enough to repeat the basic idea in a slightly different way; you have to say the exact same thing three times. Another reason to keep things short and simple.
3) Assign steps to the process.
You know, "Step 1, get three feet on a line, pre-turning your foot. Step 2...." and so on. Boil it down to the essential movements. You don't have to include all the subtle intricacies of the technique here; these are the broad strokes that define the big picture. I find you can trust the senior belts to fill in the little details when everyone pairs up. (If, however, you notice everyone omitting the same piece, or doing the same thing incorrectly, that's the time to stop class, point it out quickly and let everyone get back to it).
Once again, 3 seems to be a magic number here, whenever possible.
4) Ask if there are any questions.
Seems like a no brainer, but not everyone remembers to ask. Many times, despite my best preparation, I'll completely overlook some basic feature that's important for everyone to know, and that will almost always be the first question.
. . . . . . . . . .
All that being said, it's step two, "see it", that I've been somewhat falling short. After a solid explanation of a technique, I tend to let everyone loose to practice.
Many Ueshiba schools, I've noticed, tend to actually spend more time with the physical demonstration of a technique, and often don't explain much verbally. Which is, in part, what helped me realize I was leaving something out of the process. The part was the occasional question from a student, asking simply, "Could I see that again?"
So that's one of my new goals to work on: doing the technique at speed several times. Once a student is presented with the pieces, he needs to see how those pieces are supposed to connect before he tries it himself, right? And even though I sort of went through it while explaining it, it's somehow not the same as performing it at speed, and without talking.
Ah, there is much to learn about teaching.