Curiousity and passion play a huge role. Usually, when you learn one thing, it results in a set of new questions - now I know/ can do this, what else can I do/ learn with this? I now know this, but I want to learn more about this other thing... Wouldn't doing this to the new thing I just learned also allow me to do this other new thing... It snowballs from there.

The only assurance I can give is that it starts with a small step, and that any step is better than none. And if that step doesn't pan out, try stepping in a different direction. The trick is to get used to, and to enjoy the process of learning. Then it goes from there - the questions never stop.