I used to put my right foot on the curb (or stay clipped in and hang on to a streetlight), but I don't think that's such a good idea any more.
You really want to take more of the lane when you're at a stop. Being close enough to the curb to put your foot on it, means that you're nearly invisible to cars.
I would have to lean my bike so extremely to keep the saddle under me at a stop, that I'd never get started again. Learn to get on and off the seat quickly.
Speed comes from what you put behind you. - Judi Ketteler