"It takes seven hours to prepare a seven minute presentation".

For a 7 minute presentation I would use all of the techniques of the five minute presentation, but would briefly introduce three points into the middle section of the presentation.

The rule of three works well for the middle section of a presentation - people tend to remember three points. Think of some of the things that have been said in the teaching profession. The three 'R's - "Reading Writing and Arithmetic" or Tony Blair's slogan about the priorities for the government "Education, education and education".

Seven minutes may not seem like a great deal of time, but think what can be achieved in seven minutes. And remember nobody ever complained of a presentation being too short.