First of all, you should be building a strong list of friends on your personal page. As your books come out, announce them and ask politely for people to share the information with their friends on facebook. Ask them to please consider giving a review of work on Amazon, Barnes&Noble, Goodreads, etc IF THEY READ THE BOOK. It is fine to get reviews from friends. They are readers too. Ask them to be fair, but objective. Also, request that they do not say they are a friend in the review. I don't know why readers don't understand that peoples friends are also readers...but saying they are a friend makes people not believe the review, if it happens to be good! Using "Anonymous" for their name is even worse. That makes it look like the author wrote the review (again, if it is good).
You can also share your updates on the process of writing the book (ex: I am on final edit. Hey, I have just ordered my book cover for.... etc).
The next step is building an author page, a fanpage, or both. Since I am writing a series, I chose to build a fanpage for my main character, Gastien Beauchamp. Once you have the page up, invite facebook friends and other friends and family to join by sending an email, asking them to "like" the page once they get there. Once you have 25 fans, you will be able to have a direct link to the page and then you can stick that link on your signature of all emails, in blogs, everywhere you wish. Don't forget to include the direct link to fanpage/author page when you send the information to reviewers and book bloggers, along with your twitter, email, and buy links.
Keep people connected with your page by sending out something from that page at least weekly. Don't barrage them with things or they will unlike you. For instance, Gastien sends out announcements of reviews, and he sends out a creativity quote every week. Each time someone joins, he welcomes them and thanks them. You should, too. You can also ask questions for people to answer to get them involved, but again don't do this too often!
Search in Facebook for pages that would have people interested in your book. For example, if you write romance, search for: romance, fiction, read, etc. Like the pages. Read their information to see if you can post information about your book. Ask how often you can do that. Even if you can post every day (which is rare), don't. You do not want to be seen as a spammer. On those sites, wait a few days before posting your book again. Most don't want you to post more than once a week. DO NOT POST WITHOUT ASKING UNLESS THE INFORMATION PAGE SAYS YOU CAN! If you do, your post can be taken down and they may report you to facebook.
If you send out your link constantly to all different pages, facebook may freeze your ability to post at all for several days to a month or more. They do not share how often is too often, just be aware. It happened to me once, and I was posting to places where it was acceptable.
Ask the owners of these pages for a book review. Some will, some won't. Regardless, if you are using their pages for your own benefit, pay it forward. Tweet their link. Put their link on your blog as a favorite. Mention them on facebook. Do all of these things on occasion, and not just when it is about something they are doing for you.
Facebook can be a huge marketing tool for you, or it can get you in a whole lot of trouble. Be thoughtful, courteous and read the instructions for each page. If you aren't sure, ask them by leaving a message on their page.
Enjoy your search for facebook success. I have met many wonderful people from book pages and consider many of them friends!