From Digital Book World:
[G]etting a listing in a BookBub email is not as easy as placing an order and paying the fee. BookBub estimates that it only accepts 10 to 15% of the books that are submitted.
. . . .
I want you to see your BookBub rejection as a wake-up call. You should use it to start changing your ways. If BookBub doesn’t want you, it’s time for you to turn it around marketing-wise.
Turn-It-Around Tactic #1: Change your merchandising for the better
Even though you shouldn’t pine over being left behind by BookBub, there are compelling reasons to take a fresh look at your book merchandising.
What is online bookstore merchandising? Merchandising in a brick-and-mortar store is the art of making products look appealing to shoppers. Merchandising in a digital store includes having a great book cover, a compelling blurb, and double-digit customer reviews—25, 50, or more.
BookBub rewards authors who are actively performing these best-practice digital store merchandising methods. If your cover, sales description, and customer reviews can’t impress BookBub, what makes you think they’re good enough to impress a reader? Okay, maybe your book is too niche for BookBub. Maybe your book simply is too new. But maybe, just maybe, your merchandising needs adjustment. Here’s how:
Hire a new cover designer—a professional with experience designing today’s ebooks.
Actively solicit reviews by adding a pitch inside your book on the last page.
Get a marketing professional to help you write a powerful blurb. Or read this classic DBW article on writing blurbs.
If you correct the elements that are lacking in your book’s online profile, your offering will become attractive to BookBub’s editors—and those same things are attractive to regular customers, too.
In short, BookBub’s decision-making process is very similar to that of an actual book buyer. So if your title can appeal to BookBub, it will probably appeal to lots of other people. And whether or not BookBub ever chooses your title for a promotion, with a better cover, description, and more sales reviews, your overall sales will surely improve.
Link to the rest at Digital Book World