How to write a farce (gulp!)

I have been thinking a lot about farce recently.  We need a script for our adults’ theatre workshop next summer and comedy seems the way to go (it being the summer and all that). But how do you write a funny play? Now there’s a question (and a half).
In the name of research, I’ve been re- watching some of the episodes from “Fawlty Towers” in the hope that some of the genius will rub off on me. So things I have gleaned about a good farce:

• it revolves around a simple central idea - in "Fawlty Towers" the central theme is usually summed up in the title ("The Kipper and the Corpse", "The Hotel Inspectors", "Basil, the Rat") - and that simple idea is worked and re-worked in all it's permutations throughout.
•  the plot itself is serious (tragic even?); it is the audience that finds it funny
• similarly, the characters are funny (to us) because they are out-of-their-depth in unusual situations, not because they are comic in themselves (in fact, they ring very true-to-life)
• there is something at stake (which is very important to the characters - move that body! find that rat! - even if it is ridiculous to the audience); the more that's at stake, the crazier they act.
• much of the comedy comes from lies the characters tell (usually Basil to his wife Sybil, but John Cleese's character also lies to guests and employees alike as the need arises). The lies pile up and contradict each other and the tension escalates (all of which is painful to the characters involved but hilarious to the audience)
• pace is vital: the pressure builds continually and never lets up (this leads to panic in the characters but is key to the comedy for the audience)

So, all in all, a doddle!