How best to learn from mistakes? Here are some thought...

"Aim high and hit the mark" is a popular proverb for optimistically setting goals. It means to overestimate it from the start. Then making adjustments in order to achieve the mark. ( jeffbeals.com | Goal Setting Secrets )

To illustrate, one would have to attempt more than once, to ever hit the target closest to the bulls-eye. Before you succeed, you would have to experience some failure. Experience matters. Very seldom someone who just started could hit a bulls-eye at once. Perhaps the person, archer for example, comes to the stage and launches his arrows. First shot is a reference point (hitting band 7), but the aim is intuitively higher, an over-estimation. Then with wisdom, the archer adjusts his aim based on the result of his shot, then slightly lower. The second result was to the left band 8. Then finally he adjusts his aim to hit the bulls-eye on the target; success. “Without failures, you cannot measure success. In a few words, failure is a part of success (brainzmagazine.com)”

All these effort won't be possible if one does not have patience and perseverance. (Stanstead College | Failure Makes You Stronger). Adding some spice to that is endurance, we have the proverb "what doesn't kill you makes you stronger" means that you need to be able to endure the thing you need to accomplish.

"This isn't a one-shot only world - just do better next time" - (alicedartnell.com | failure is actually a good thing) The pains of failure helps us to remember our mistakes and follow-through. But unfortunately in life some things cannot be achieved. In this case, be realistic. So says de Botton - "There isn’t only one script for success ...  There’s always a Plan B." (Broadview Magazine | How failing has changed my life for the better)