Here are two key book promotion tips for any book, any author, any ebook . . .
The best time to start promoting your book is when you have the idea for your book. Right at that time of inception, start talking about your book. Start sharing your thoughts via your social networks and blog.
Bookstores don’t buy books (they simply rent them). It’s readers who buy books. So ask the real buyers to buy your book. Promote to them.