I feel, In trading or investment, or even for the whole life itself, managing risk properly is the main crux. In other words, To keep away from liquidations of any sort is of the highest Priority.
For the same, the main active lesson is trust none, including possibility of a new opportunity when we are presented with an opportunity for the time being as part of best possible profits. I mean, sometimes we may have to take What's been presented instead of hoping for Better profits which may Or may not arise.
But, the dilemma is that, if the knowledge and experience is perfect to the best along performing aptitude, then It's risk takers who gains huge profits even by avoiding small profits by waiting for right timing to exit only with huge profits.
Such players focus on technical skills rather than mere Luck Possibilities.