When I first got clipless pedals, I had to plan out my stops--"Okay, unclip at the twig/"Stop Ahead" sign, whatever...Unclip, apply brakes...Yay! I didn't fall over!"

My boyfriend's advice to me was to try riding with one regular shoe and one bike shoe (the foot you put down). That way, you get practice clipping in and out, but you still have the other foot to catch yourself. Didn't stop me from falling twice on my first time out with both feet clipped in, though.