At this point, as a start, I was trying to reach the largest market I could while still putting some focus in place rather than leaving the estimates so broad.

-Shannon
LLBR

I have also used Facebook advertising successfully to get traffic for my “How to be an Author Workbook”. However, I disagree about the use of keywords and also restricting your audience.
You need to restrict your audience so the advert is targeted – this is the beauty of Facebook ads that set them apart from Google PPC.
For example, if you are a romance writer, your market is Female aged between 18-65 approx – or perhaps you want to target even further e.g. boomers might buy the most romance novels so target Female aged 45-65 who like “romance” and “reading”. Perhaps your book is set in New York or aimed at the American market, so target geographical area USA, East Cost or NYC.
This means you will get more targeted impressions for your marketing $. Instead of your impressions being flashed at people who are not your target market, just have them show up to those people who may actually click through.

Authors should know their target market for their book so should be able to target these adverts really well. Thanks for the article – it is a great overview of the process!