I was reminded of this Secret of Adulthood just again last night. At a party, I was talking to someone I'd known from law school, who had gone on to be a very well-established artist.
I asked her how she made this (fairly unusual) transition. It was a long, interesting story, and at one point she said, "I got to know a lot of artists, just from going to shows and doing all the things that interested me." Those artists didn't hire her, but knowing them helped her make the shift.
Plus I was recently at another party, also with a bunch of friends from law school and from my clerkship with Justice O'Connor. They were mostly working as lawyers or in business, and they said how funny it was that many of them now were the clients of others, and that it was fun to work together in this way.
Of course, this observation wouldn't be true in every kind of career, but it does seem to me that when we follow our natural interests and inclinations, we readily form the relationships that can help us to succeed.