Learn to discern the difference between what is skillful and what is unskillful. Choose to focus your attention on developing and cultivating skillful thoughts that lead to skillful behavior (speech and action).
We sometimes have thoughts that are unreasonably self-critical, or self-disparaging, or even self-hateful. Some of these thoughts were messages we heard during childhood, others we picked up along the way as adults. These kinds of thoughts are unskillful, they are not conducive to wellbeing or happiness. So, upskill. Think better thoughts, and keep practicing thinking better thoughts so skillful thoughts replace, or have more prominence than, unskillful thoughts.