- Take initiative.
- Make things.
To elaborate on these two points a little: put yourself out there. You have no idea what you are capable of until you do. Start things. Persist in them even when they get difficult.
Sure, that is not all you need to do in order to be successful. There are other things to consider. You need to figure out how to earn a living. You need to figure out how you work best with other people in the various settings you will find yourself in. You need to figure out (warning: thought-stopping cliché ahead) what you are really passionate about. And so on.
The details will depend on who you are and your environment.
But if you do the two items listed above, you will have no trouble figuring everything else out when you need to.