What I've been taught is
pull up at the kerb
do your full observation sweep for reversing (right shoulder, right door mirror, rear view mirror, left door mirror, left shoulder)
and move off from the handbrake (no accelerator).
As you do the manoeuvre, face backwards and watch the road behind you, but every car's length or so turn round briefly and check forwards and all three mirrors.
there are THREE points at which you do a full observation sweep - when you move off, before you start to turn (so as not to swing out into traffic) and as you straighten up in the side road. The rest of the time you watch backwards and check forwards every few metres as above.
I'm crap at doing it based on watching the kerb out the back alone, but I turn around to check the front *very* often so I can keep an eye slyly in the left door mirror and do the manoeuvre through that.
(sorry not relevant, but I'm a stickler - it's KERB please! A curb is the edge of a sidewalk at the side of the freeway. We have kerbs in Britain...)