I fell 3 times in the first 2 days. Once when I stopped, but only clipped out 1 foot and was leaning the wrong way.
The other two falls were due to my failing to clip in fast enough when starting, and having to go uphill.
I've since learned to always put the same foot down when stopping (left foot for me), and when I'm clipping in, if I don't get it right away, to keep pedaling with the other foot until I'm able to get it.
So far (knock wood), no more falls.
- Don