1.) Facebook Ads are still the number one way to reach out to "hyper targeted" cold prospects and get them on your
2.) mailing list. Because Email marketing is the number one way to "market" ..period.
3.) Influencer marketing, or better said outreach, is the fastest way to the top, but not possible for beginners. So I would concentrate on developing relationships with influencers for later launches of your better more polished books.