Learning the 'friction zone' of first gear is also what they teach motorcycle riders to learn the manual transmission. Since 95% of operating a transmission is engaging the gear without lugging or burning the clutch plates, engaging into and out of 1st gear is an excellent exercise.
On a motorycle, you put it into first and slowly engage the clutch at idle throttle until the bike begins to roll forward. Disengage the clutch, rock backwards, and repeat.
In a car it's much the same, engaging the clutch at IDLE throttle until it begins to move and then releasing it to come to a stop again. In teaching this way, the learner also avoids burning up your clutch by giving it WAY too much gas. Any vehicle with a stock clutch should begin rolling with clutch engagement and NO throttle.
Once they've mastered rocking back and forth, they're 95% of the way there.
RE: Downshifting, it's generally advisable for novice to intermediate drivers to fully engage the clutch while slowing to a stop, rather than attempting to downshift through all (or some) of the gears. Because proper downshifting requires rev-matching, it should only really be done in an emergency or once you've mastered it. Even professional drivers heel-toe shifting do not precisely match the revolutions of the flywheel during downshift, and do introduce wear into the transmission. Even though I'm capable, I rarely downshift through the gears UNLESS the conditions merit using transmission breaking or if I intend to accelerate again quickly.
Also, I shift at 8500-9000 RPM.
