Methods to Maintain Peace of Mind?

Could any of you please share your most effective methods of maintaining peace of mind in the face of adversity? By "peace of mind" I mean the absence of negative emotions such as anger, regret, boredom, fear, frustration, loneliness, envy, etc. I will start the discussion with one of my favorite techniques, which I call "elimination of judgments," which can be very effective in alleviating disappointment, frustration and anxiety.

Elimination of Judgments. One should always keep in mind that events are interconnected through the operation of physical cause and effect. Thus, apparently negative experiences can precipitate positive experiences, and apparently positive experiences can precipitate negative experiences. If one were able to go back in time and eliminate a particular experience, one’s entire life might change as a result, and whether it would change for the better or the worse would not be knowable. Therefore, one will generally never know whether an apparently negative experience is truly negative in the overall context of one’s life, or whether an apparently positive experience is truly positive in the overall context of one’s life. As a result, one should eliminate judgments with respect to whether any experience is truly positive or negative. Such elimination of judgments strongly promotes equanimity and peace of mind—before, during and after one’s experiences.

I look forward to learning about additional techniques to maintain peace of mind. Thank you for your time.