To do your best. I've met a lot of people who weren't very bright or accomplished, but every day they made a conscious choice to get up and work hard at something. All of those people are financially better off than me. This is with hindsight, a younger me would have said 'reading and learning new things'. If I wasn't such an arsehole I would have learned how to be nice to people and to listen better, I never realised how important interpersonal skills would be If we are just talking random skills, then laying bricks and coding are pretty useful