I've had a few people write to me and ask about the marketing posts I did a couple weeks ago. Several have wanted to know, "When should I consider spending my own money on my book's publicity?"
The answer is probably, "When you feel the marketing people at your publishing house aren't doing enough," except that NO author ever really believes the marketing types are doing enough for their book. (It's true. I've seen bestselling authors who are getting full page ads complain about the lack of effort from the marketing staff.) I suppose every author would like to see the marketing department try harder, do more, be more creative, and get away from doing the same things that don't work, all for no cost. But the publishers are all trying to do their best. One young publicist might have 20 or 30 books she's working on, so your book may not get a ton of attention.
So again, let's just work on the assumption that YOU are in charge of the marketing. Anything your publisher does is great, and by all means you should express your appreciation for them sending out review copies or setting you up on some blogs to talk about your book. Hey, at least they're doing SOMETHING. But yes, it's possible your book may need a boost when it comes to publicity if it's really going to grab some attention. Figuring out what to do next is the key.
A lot of authors want to simply hire an outside publicist. That may work, or it may be an expensive mistake. Let me suggest that the first "outside" person who needs to get involved is you. It bears repeating: YOU are in charge of marketing your book. You. Not the publisher, who will help you but may not do all that much unless you're a proven bestseller. You. Nobody else knows your message as well; nobody else is as committed to your story as you are. Nobody else has as much riding on your book as you do. So just assume you're going to take charge of your marketing.
That means you're going to have to educate yourself. I can recommend some basic marketing books, such as marketing textbooks to get you started, but good books specifically targeted to book marketing include David Cole's COMPLETE GUIDE TO BOOK MARKETING, Steve Weber's PLUG YOUR BOOK, Jay Conrad Levinson's GUERRILLA MARKETING (there's a special one for writers), Penny Sansevieri's RED HOT INTERNET PUBLICITY, Chris Murray's MARKETING GURUS, David Scott's NEW RULES OF MARKETING AND PR, Lissa Warren's THE SAVVY AUTHOR'S GUIDE TO PUBLICITY, Shel Horowitz's GRASSROOTS MARKETING FOR AUTHORS, John Kremer's 1001 WAYS TO MARKET YOUR BOOK, Tim Berry's ON TARGET, and the books by David Rising. Rob Eager of Wildfire Marketing has a new book on marketing coming out with Writers Digest soon, so look for that one. Consider spending a couple hundred dollars to educate yourself first. You can also think about purchasing a used copy of something easy like MARKETING FOR DUMMIES and SMALL BUSINESS MARKETING FOR DUMMIES. That will get you started. Do that before you spend money on an outside specialist.