What is success to you? How to be successful in life? To some, when they think of success, they imagine wealth; others want power; some just want to make a positive impact on the world. All of these are perfectly valid, indeed success is a concept that means different things to different people.
"The ability to work hard and respond resiliently to failure and adversity; the inner quality that enables individuals to work hard and stick to their long-term passions and goals." The definition of grit almost perfectly describes qualities every successful person possesses, because mental toughness builds the foundations for long-term success.
Learn from your mistakes, and those from others too, but let them go. The past is just training; it doesn't define you.
When something bad happens, see it as an opportunity to learn something you didn't know. When another person makes a mistake, learn from it and see it as an opportunity to be kind, forgiving, and understanding.
Sometimes you have to look back to go forward, learning from others' experiences and soaking up their infinite knowledge as you go. Luckily, the decades before us gave rise to some of the brightest minds in history-and judging from all their accomplishments, they definitely knew a thing or two about success.