How come Phoenix has to be so dang smart?
What I've always tried to do is, start a few days before the biggest ad (BookBub), and also have ads the day after BookBub, to try to smooth the spike as she says--both the ramp up and the ramp back down. For my upcoming promo, which is 5 days, I've got about 15 sites going, including BargainBooksy, ENT, BookSends/Pixel of Ink, Fussy Librarian, etc., happening around the BookBub promo. Also as Phoenix says, having some of those promos happening at the beginning helps your book move up and increases the chances that it'll be on that first Countdown Deals page (for whatever that's worth--as I said, not sure how many customers navigate to that). But also that it'll rank high in your categories for longer on the pop list as well as the bestseller list.