Everybody makes mistakes from time to time. Mistakes exist so that you can learn from them and avoid repeating the same mistakes. And one of the best ways to do this is to place it in writing, hereby known as the "D'oh! List" (named after a certain clumsy father-figure from The Simpsons).
By jotting it down on pen or in a .txt file, it allows you to face your mistakes instead of just relying on just your memory. While this isn't an entirely new idea, for some people the act of
writing down their mistakes makes it easier to backtrack and not repeat
the same patterns.
The benefit of writing it down is that it's easier to recognize your own patterns when it comes to making certain mistakes. From there, you can train your subconscious to avoid certain triggers that might lead you to repeating the same mistake. You can also include in the list a collection of better solutions so that next time you do something, it gets done right.
For ideas on how to write up your own D'oh List, check out Lifehacker.