I fell three times the first day I rode clipless. Shimanos that are clip one side, platform the other. It really hurt, twice on the road and once on a soccer field. Or maybe it was four times, and twice on the soccer field?
DH told the BSGs the next day...who told me is it easy to unclip left and lean right (or vice versa) and to practice on a field. My best recommendation for practicing is pine needles! Very soft, if there's room under the trees! I work on clipping in, starting up, and then clipping in the other foot. The day I unclipped both feet at once in an emergency felt great (aside from the dog coming after me).
I put clipless on the commuter first and then started riding clipless on the cross bike because it was new and shiny. And I still have pedal problems some days...but the BSGs told me they still mess up sometimes, too, and that made me feel better (because I know it is true, and they ride a lot).