I want to add that along with letting kids figure it out for themselves, or explicitly teaching them might be supplemented by examples of failure. e.g. Steve Jobs getting kicked out of Apple; Usain Bolt stalling early in his career; and of course Edison's "I haven't failed 1000 times; I've discovered 999 ways that don't work". But these are distant. Seeing an actual person you know fail and then succeed right in front of you is very reassuring. This is why, when I was demonstrating/tutoring at uni, I never tried to cover up my mistakes in front my students. Instead, highlight them, and show how to recover from them. I'm pleased to say those students did really well.
I want to add that along with letting kids figure it out for themselves, or explicitly teaching them might be supplemented by examples of failure. e.g. Steve Jobs getting kicked out of Apple; Usain Bolt stalling early in his career; and of course Edison's "I haven't failed 1000 times; I've discovered 999 ways that don't work". But these are distant. Seeing an actual person you know fail and then succeed right in front of you is very reassuring. This is why, when I was demonstrating/tutoring at uni, I never tried to cover up my mistakes in front my students. Instead, highlight them, and show how to recover from them. I'm pleased to say those students did really well.