on Jane Friedman site:
As you probably know, Amazon allows ebook pre-orders for KDP authors, which helps level the playing field between traditionally published authors and those who self-publish through KDP.
Even Amazon will tell you right upfront that pre-orders are great for building buzz.
True. But there is a caveat.
If you’re a new author with no reader base (yet), you really have to power through your pre-order and work it harder than you would if you had a series of books already out there.