+1 on practicing on a grassy area.
I had SPD pedals for years. I always clip out with my right foot first. Due to an old ankle injury, it was most comfortable to clip out by turning my ankle inward with my foot at the top of the pedal stroke.
After getting a new bike, my knee started to hurt so I switched to Speedplay pedals. With the Speedplays, I had to relearn to clip out, because it had to be done by turning my ankle outward with my foot at the bottom of the pedal stroke. I had to overcome a habit that had become so ingrained that I did it without thinking about it.
So for my first few rides with the new pedals, I repeated the phrase "down and out" to myself periodically through the ride, and especially whenever I was in a situation where I might need to stop and clip out. Down and out, down and out, down and out. Before I knew it, the new way of clipping out had become second nature to me.
So, try coming up with a phrase to remind you what you have to do. Something like "right foot down" or "foot down on the ground" or anything to remind you that you need to have your right foot on the ground before you try to unclip left.
Re: the fear, bear in mind that everyone who uses clipless pedals has fallen because of them. It's a rite of passage. Welcome to the club!!
- Gray 2010 carbon WSD road bike, Rivet Independence saddle
- Red hardtail 26" aluminum mountain bike, Bontrager Evoke WSD saddle
- Royal blue 2018 aluminum gravel bike, Rivet Pearl saddle
Gone but not forgotten:
- Silver 2003 aluminum road bike
- Two awesome worn out Juliana saddles