> I read an interview a few years ago where a reporter asked a writer what was the difference between authors who made it and authors who didn't. The writer said that the ones who made it stuck with it. They just kept on writing despite years and years without strong sales or recognition.

That's a bit of a platitude though, because there are plenty of writers who kept with it but who spent their entire lives, or the majority of their lives, in abject poverty and little to no recognition. I get the general advice though, but it isn't a guarantee of course.