Pick a foot to unclip, and stick to it.

In slowing to a stop, there's a moment when the forward momentum is no longer enough to hold the bike upright. Own that by picking the foot to put down -- and unclip it and induce the bike lean rather than waiting for it to happen.

I kept falling (or crashing) until I figured that out. I'd stop and then try to figure out which way the bike was going. Now, I always unclip the right foot, and I haven't fallen in years. And I end up changing the cleat on the right foot at least twice as often as the left.