Four steps: choose a field, learn enough to get to the frontier, notice gaps, explore promising ones. This is how practically everyone who's done great work has done it, from painters to physicists.
It’s enormously disorienting to simply say, “I don’t know.” But it’s infinitely more rewarding to understand than to be right — even if that means changing your mind about a topic, an ideology, or, above all, yourself.
When I was a kid, it seemed as if work and fun were opposites by definition. Life had two states: some of the time adults were making you do things, and that was called work; the rest of the time you could do what you wanted, and that was called playing.