Book marketing and promotion is a thankless and often unfulfilling job. What works for one author may not work for another. And the promotional ploy that works for a nonfiction book may produce negligible results for a novel. A good example of marketing advice that can be hit or miss is the Amazon Kindle title, Book Marketing Primer. It’s loaded with ideas, some of which are relatively useless and some of which you may have already employed. But the section entitled “Author Insights: Advice on Marketing” (Kindle Locations 486) is worth a look if only because it’s a compendium of different marketing plans and ideas from a number of different authors. You may find something of value for you. The book is a free Kindle Edition eBook, available directly from Amazon, so you can’t beat the price!
https://www.amazon.com/Author-Marketing-Primer-Kindle-Press-ebook/dp/B01F7W9JFW