More than ten years ago, I attended my first writer's retreat sponsored by the Highlights Foundation in the Pocono Mountains. My mentor was Joy Cowley, a notable children's author from New Zealand. Joy not only wrote for children, but wrote for adults, too. It's just that her money-maker had been the children's book, "Mrs. Wishy Washy," and that sent her career as a children's author into play.
Joy was a fun person to be around. Everyone liked her and appreciated her. At that time, I began working on a short read about an alien girl (mentioned in a previous post) and learned from her that the story should be extended into a novel. Also, she emphasized that I was a science-fiction writer. Later on, I would learn I was better at writing humorous horror for the intermediate grades thru young adult.
So, I began giving some serious thought in writing my first book of science-fiction. I described it as giving birth from my brain. Completing this work, gave me a better understanding about writing a work of fiction.
It was a thrill to meet so many talented would-be authors. One in particular, Mariam Davis Pineno, a retired music teacher, who was a talent. After the retreat, we kept in touch and two years later met up again at another writer event.
Unfortunately, Mariam was never able to obtain a publishing contract and ended up self-publishing her own work and was able to promote her work through school visits.
There are many authors who do that and there's nothing wrong with that! However, it is time-consuming and quite a gamble when it comes to making a profit, especially in the fiction field.
If one is going to self-publish, the books that might sell are those in the non-fiction category.