Things to focus on in a model lesson A model lesson is a usual element in interviews for the faculty level positions. Normally this is not a full lesson but a 15-minute version which is performed in absence of actual students for just a few professors from a hiring committee. It is supposed to demonstrate "your teaching style", but by design this is clearly a different enterprise: you should "act normal" doing "the same" things 


in a different time-frame, 
for a different audience, 
with completely different motivation and 
under exorbitant cost of failure.


Having said this, I also acknowledge the model lesson as indeed a much needed element of the interview, which helps to assess a candidate's set of relevant skills.

The question is how one can ideally prepare to give such a model lesson. Putting aside obvious things like "structure of the talk," "clear slides," "projection of the voice," and "body language", which normally should be already trained by experience, are there specific things that should be taken into account for the model lesson only? What about techniques like jokes, questions to the audience (e.g. how many of you are familiar with the definition of the derivative), work in pairs, which you probably use in a real classroom &mdash; is it a good idea to demonstrate them in a room full of senior professors? I am a little confused.
Having done this, I'd advise:


Take it really seriously. In places where candidates are judged equally on teaching and research, the model lesson could really make the difference. Strong researchers may neglect it, relying on their publication/citation record.
Make sure you prepare for the expected audience (in my case, 1st year students), not the actual audience (academics).
Feel free to use techniques you would use in a classroom, but then use "time jumps" to indicate that the activity has taken place. The problem with this is that if you have follow up questions, there may be no answers and the lecture may fall flat.
Don't forget "learning objectives" and "lecture structure" up front, and other guidelines for students throughout (though you probably can only show one such thing).
Practice more than you would practice for an actual lecture.
No corny jokes. If you cannot tell whether a joke is corny, then assume it is. In fact, beware of jokes. Relying on natural humour is probably better.