(1) Copy editor, (2) Editor, and (3) Cover Designer.
None of these elements guarantees success because getting exposure and marketing are whole different animals. Still, you get the point.
When I first produced The Long Walk, I didn't know what the hell I was doing. Now that I am producing Not Your Abuelita's Folktales, I have a copy editor and new cover designer. In fact, I would say that besides my last two freebies, the new cover for the collection best fits the genre.
Below is my redo of my first short pub, The Long Walk. The cover and the design are a lot better, but the cover doesn't quite say barrio zombies. It's a work in progress.
My point is that I'm doing things better, and right. I also have a great editor who is going to look at my novel The Harvest. That is a huge step forward for me.
The next thing may be hiring a professional cover designer, but we will see.
Keep doing better. #barrioblues