I think I have a strange answer: The only things that work for me are spite and a desire to not be a dick. I will not overcome perfectionism for my own sake, but wanting to model handling mistakes gracefully for junior colleagues/kids enables me to do it.
If I don't mess up, I can't fix it, and the world could really use more people who are willing to admit fault and work to repair mistakes. We all make them; I find lots of people with perfectionistic tendencies (myself included) hold ourselves to a much higher standard than others, so I just created a new impossible standard to meet that makes it possible to mess up, admit it, and move on. (Now the impossible standard is that I don't possess infinite grace about my mistakes, but...)
If I don't mess up, I can't fix it, and the world could really use more people who are willing to admit fault and work to repair mistakes. We all make them; I find lots of people with perfectionistic tendencies (myself included) hold ourselves to a much higher standard than others, so I just created a new impossible standard to meet that makes it possible to mess up, admit it, and move on. (Now the impossible standard is that I don't possess infinite grace about my mistakes, but...)