An expert is “a person who has made all the mistakes that can be made in a very narrow field.”
This is how he or she became the expert. As Zen master Shunryu Sukuzi said, "Zen is one continuous mistake."
I suppose this means teachers must experiment with many approaches and report constant failures. But there are also implications for students. The article discusses studies that have tracked the efficacy of two different types of praise: 1) the "you-are-so-smart" kind, and 2) the "you-worked-really-hard variety. (Those are not official clinical terms.)
Long story short: Kids who receive "smart" praise are less likely to take on harder tasks, less likely to benefit from mistakes, and more likely to get discouraged. Essentially, they are protecting their self-image as the "smart kid" and are unwilling to expose themselves to situations that threaten their identity. Students who are praised for their hard work are more willing to take on new tasks and challenge themselves.
We've tried this at home with our oldest child and her writing practice (she's 4.5, learning to write her letters and a few words, etc) and it seems to work. We praise her effort, her focus, concentration, etc. and try to avoid saying "you're so smart" after she completes a task. This way, she still gets praise and feedback but it's directed at the work itself.
This is impossible when it comes to her looks. I must say, "You're so cute!" instead of "You worked very hard to maintain your appearance!"