While I've seen a lot of authors approach their FB pages in different ways, one thing that makes any FB page "successful" (i.e. gets more traffic/more likes) is viral content. Viral implies that it is shared across the web (or FB) reaching more people than just a single share by your page. Content can be anything that applies to your brand (i.e. you as an author, your book, your interests).
Take into consideration what types of things are often shared on FB.
Quotes are pretty common among FB content and FB shares. Here are two quotes I added to images and shared on my FB page. Notice how they apply to my brand (fantasy author).
I also created this one with my own text because it applies to my brand (fantasy books and strong female characters).
Lastly, I created this to help promote the series in particular. I have more of these cat photos/text to share on the page. I chose cats because they are popular and they are featured in our book.
So consider what your brand is and what content you can make to add to your page and get people to share. Also note that when it's time to promote your book asking family and friends to share any posts about your book is helpful. Don't ask them to share every post you make (unless you want to be annoying) but getting them to share your posts about your actual novel will get more eyes on that post and more potential sales.