What Kano said...except you don't actually have to stand on the lower pedal to unclip. Just unclip the foot from the top pedal then stand on the low pedal and step down with your free foot when you come to a stop. You can do this well ahead of your actual stopping point. I think the falling thing is just experience. Also, it helps to spray your pedals with WD40. Makes getting in an out a LOT easier. But it will attract dust so be sure to clean and relube often. After falling a time or two it really makes you pay attention more when slowing down and/or turning. I still unclip my top foot "just in case" when slowing down...that way I have a quick out.
As we must account for every idle word, so must we account for every idle silence." ~Benjamin Franklin