How do you stop yourself from making the same mistakes unintentionally?

They say people can change, but it's hard to write with a left-hand when you've been been using your right arm since preschool.How do you stop yourself from making the same mistakes unintentionally?
The first step is to realize your making a mistake. This isn't usually something you wake up and realize. I don't know what your referring to on your personal level. Friends and family are usually the ones who can see it, and a true friend or someone who cares about you will try to point this out. So your answer is it's not just from within we learn. Support, guidance and the willingness to want to correct whatever the problem is helps to educate us . If it is unintentional and your just learning this then the best way to show it is to listen.