As long as there is gravity, people will continue to fall. Practice more = fall less, it is really that simple. Just avoid the temptation to stick a hand out to break your fall, that is a good way to break a wrist or clavicle. For your typical clip-out failure, just pull your chin to your chest and try to land spreading out the impact through your hips, ribs and shoulder. Don't gasp or hold your breath, breathe out forcefully at the moment of impact.

You're going to tip a few times getting used to clipless, everybody does. I tipped twice on group rides last year and once on my own. I used SPD and what helped me was to lower the tension on the retention spring and to go with the multi-release cleats. I also ride double sided pedals so that I can clip out and ride the flats when in stop-n-go traffic. If you try that approach, I found it good to force myself to do the heel twist to "clip out" even when I'm not clipped in, just to make sure I don't develop any bad habits.