Having watched my fair share of synth tutorial videos (Groove3, YouTube etc) I feel qualified in offering a few tips for anyone thinking of putting together their own synth tutorial video.
1) Start by saying how awesome and versatile the synth is. Point out that the synth is capable of producing any sound from "growling basses" to "cutting leads." Remember that nobody except Skillrex or Deadmaus fans will be watching your video.
2) All sound demonstrations must be done with a bare sawtooth oscillator. At no point during the tutorial should you make any kind of musical noise or create anything that sounds like it could come close to being used in a piece of music.
3) The raw sawtooth oscillator should be at least twice as loud as your speaking voice. Under no circumstances should you make any attempt to balance the levels of your voice and the synth. Remember that a lot of people will be watching your video with headphones on for the express purpose of developing tinnitus and/or high frequency hearing loss. This is another reason why the bare sawtooth oscillator must be the basis for all demonstrations.
4) Never attempt to play anything musical on your keyboard when demonstrating sounds. You should either bang the same note repeatedly (trying not to adhere to any particular rhythm) or simply mash the keyboard with your fist. Remember, nobody is in the least bit interested in what this synth sounds like in a musical context.
5) When demonstrating any kind of filters or effects, be sure to choose the most dissonant combination of parameters. If anything starts to sound the least bit pleasant, crank up all of the parameters to their maximum state. This particularly applies to things like ring modulators, frequency shifters etc. It helps to imagine that it's 1965 and you're working for the BBC Radiophonic Workshop on some Dr. Who sound effects.
6) When demonstrating any parameter, it's important to sweep between the minimum and maximum values as fast as possible by dragging the mouse up and down at a high speed. This is the only way in which the viewer will get a sense of what that parameter does. Make sure you sweep it up and down for way longer than necessary. It might be helpful to spend a good two minutes aimlessly moving the knobs or sliders in a module toward no end in particular, while banging a single key repeatedly (see no. 4). Remember, this video is as much about you yourself having fun as it is about teaching the student. Go crazy! If desired, hand the mouse over to your cat at this point.
7) Finish the last video of the course having not once created one single musical sound that wasn't a dissonant sawtooth. Remark that "of course, the possibilities are endless."
So there you have it.