The highest value skill you can develop is agency.
Agency is your capacity to get something done. It doesn’t matter what the task is, high-agency individuals will find a way. They are creative, resourceful, relentless, and imaginative.
Agency needs optimism. You need to believe that whatever you want is possible and there is a way to make it happen. I subscribe to David Deutsch’s view on problems & optimism in that all problems are solvable unless dictated by the laws of physics. To doubt that takes away your own agency.
If you want to live a great life and do great things, it’s not hard. You just take action on the things you want to do, no matter what. You believe they are possible, and you figure them out. Repeat that enough times and you can do anything.