Judging from my personal experience and that of every other CFI I know, you may think when you walk out that day with your shiny new CFI certificate that you did it. You are now a full-fledged instructor. NEGATIVE. You just have an instructor certificate.

I don't think I really got the "hang" of teaching the fundamentals of flight until about my 400th hour of dual given. And I don't mean I didn't know how to tell them to keep the wings level, I just mean that I didn't know how to tell when they truly had basic attitude control down well enough to move them on to other things. Flying an airplane is an extremely complicated task, and teaching someone how to do it is even more complicated. There are SO many little quirks about individual people, especially when you stick them in a little aluminum tube and make them do tricks 3,000 feet in the air. No book, no class, no mnemonic can teach you about that. You just have to go do it over and over and over again with different people from different backgrounds and education levels, and then maybe you can start calling yourself an instructor.

I think I might have been an instructor with another 500 hours of dual given, but I'm off to drive the bus now.