How do you do it? You do it.
You write.
You finish what you write.
You look for publishers who publish “that kind of thing”, whatever it is. You send them what you’ve done (a letter asking if they’d like to see a whole manuscript or a few chapters and an outline will always be welcome. And stamped self-addressed envelopes help keep the wheels turning.)
Sooner or later, if you don’t give up and you have some measurable amount of ability or talent or luck, you get published. But for people who don’t know where to begin, let me offer a few suggestions:
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