This is one place a public relations specialist can really help, because that person has already established contacts with newspaper editors, book reviewers, TV and radio personalities, podcasters, and others who can help get the word out about your book. A PR professional knows which places are most likely to be interested in your book, how to approach them, and how to help you prepare for the opportunity.
The timing here can be tricky (and that’s another reason to get professional help). You want to build a buzz and get people excited about your book, but it isn’t yet available for purchase.
One solution is to set up a system to manage pre-launch sales. That way, you can drive interested people to a website (yours, or your favorite indie bookstore’s) to pre-order your book. Even if you don’t set up a pre-launch sales plan, you should still include a call to action in all your PR efforts. At the very least, ask people to go to your website for more information; once there, they can sign up for your mailing list to receive updates about your launch plans.