Make sure they can find your book

Get a domain name — a URL — of the full title of your book.
If your book title is really long, then you’ll also want to come up with an easy-to-remember shorter domain name, but get the full name, too.
Christine Clifton, author of the book, You Don’t Have to Shout to Stand Out, shortened her book title to: No Shout Stand Out. NoShoutStandOut.com.
It makes it a lot easier for her to share that URL with potential readers.
For SEO purposes, you’ll want to build your book site on that longer, full-title domain. You can always re-direct, or forward, the shorter domain to that same site if you’re not using it for anything else.
But keep in mind that you can forward a domain name to anywhere you like. So you may want to direct people to your Amazon sales page, to a blog post, or to a specific page on your site.
Having a short, descriptive domain for your book will make it easy to share so that it makes it easy for your potential readers to get exactly where you want them to.