I mean, some of it is luck. My sons are good academically, but rubbish at sport (not for want of enthusiasm!) and average at music - there's nothing that's going to change those - the talent just isn't there. I was the same - despite loving netball, I was never going to be on the team I just wasn't any good at it!, and I enjoyed my various instruments, but again, just didn't have much musical talent. However my academics were good, and I've got a nice comfortable life from that instead.
Whereas my eldest has a friend at school who's literally good at anything he touches - on the first team, high grade piano, always near the top of the class, and he's a lovely lad to boot!
II think that as PP have said, being willing to take some risks, and put yourself in the way of luck is important (if your starting from little), as is future planning, and being able to delay gratification (eg. being able to save, rather than spend every penny you have)