One of the most popular types of books you can publish today would be journal-type books—the kind that help people figure themselves out through actionable tips and space for essays and the like. Part activity book, part inspirational literature, this creative publication can make you a successful author. You just need a good cover to get people to buy it.
Start with this Canva template. It has a pale blue background with lightbulb icons patterned all over it, plus bold painted font for the title. Adjust the colors and font, and reposition all the lightbulbs for print and ebook editions.