Success versus Failure in the Classroom

"Success is a lousy teacher. It seduces smart people into thinking they can't lose." - Bill Gates.

We learn so much by our failures. It is through trial and error that we come up with the creative solutions. Yet as a teacher, how do we make students comfortable with failure? (Not necessarily the "F" grade, but the mistakes we make along the way.) When I walk around the classroom offering comments on student's work, they usually trend toward the positive, probably because when I offer suggestions for improvement or change, sometimes the students get defensive. When I look at times when others have given me suggestions for improvement or change, I felt defensive also! How can we change this?

At the end of each class, I ask the students to share what problems they encountered and how they overcame them. I always praise their ability to do so. I sometimes do this when I conference with them. Although when I conference with them I am usually asking them to rate their work. They are pretty honest in doing this and sometimes I tell them they did better than they think.

Would requiring revisions take the sting out of "not doing something right"? So often we grade only once and that grade is what they end up with. Is that the cause of their fear of failure? Or is it ridicule by their classmates when they don't know an answer or when they make a mistake? I know my middle school students love to laugh/share the "Fail" pictures/websites, does that contribute to the climate of being afraid to fail?

I don't really have the answer here. As the leader in the classroom, I definitely need to lead by example though. How should I encourage success through mistakes?