IMHO, the best way to teach anyone to drive stick, if they've never tried it before:
drive them yourself to a big empty parking lot with few obstacles or anything to hit.
have them figure out how to launch the car (into a slow rolling speed in 1st) from a dead stop using the CLUTCH ONLY - no gas. any properly running car should have the juice to do this. have them do this over and over until they get the feel for the clutch engagement. once they learn that the clutch is not an on/off switch and understand the finesse involved, everything else flows from there - but in traffic or any traveled roadway is NOT the place for someone to figure out how to use a stick, from scratch.
true story: when I was 13 years old, one of my father's friends was giving me a ride home and he pulled over in the neighborhood about a mile from my house (in a 1974 Alfa Spyder which was only a few years old at the time) and let me drive it around - the first car I had ever driven... and of course it was a fickle Italian manual. He talked me through the above, the best driving lesson I ever had. I don't think I got out of 2nd, but I "got" what driving a manual was all about. It was like 6 years later before I got my own car with a stick, the first one in my family; but in the interim, I could jump into any other manual car and drive it with confidence.
my 2c,
-Peter
04 Mazda 6s V6 MTX, in service 10/28/03

02 Subaru Impreza Outback Sport 165HP 4cyl auto AWD
former: 95 Mystique LS V6 MTX [11/14/94-5/19/04]