"The aim of marketing is to know and understand the customer so well the product or service fits him and sells itself."
I think one of the greatest challenges of being a novelist is balancing the craft side of writing with the business side. Both are a constant education, but technology advancements are pushing the business side at a much faster rate. Some marketing and sales techniques that used to work well in the past don't necessarily carry the same impact now--and in some cases can even backfire. On the other hand, authors now have an opportunity to reach readers on a global level very inexpensively and very rapidly--something that I think will long-term have a positive impact on the industry.
One marketing book that I recommend for any author is the 2010 edition of Guerrilla Marketing for Writers. It's very detailed, and for me it's become more and more useful as my writing career has grown. I also like Seth Godwin's books, mainly because he has a fun attitude about the subject and is very innovative in his ideas.
The following are some ideas and tools that have helped me personally:
1) Offering rough draft excerpts/related short stories online for free
This is somewhat counter-intuitive, but it has worked for me. With having a series, developing reader interest in the current book results in the previous ones being bought later. I consider it similar to catching a TV show in mid-season and wanting to catch up.
2) Business cards, postcards, posters, etc.
In part to make your life easier when talking to people about your book or books, it's worth investing in some basic marketing materials. This doesn't have to be expensive, and I've never used debt to do it.
VistaPrint is very reasonable for business cards and postcards. Bookmarks make great giveaways as well, but I prefer postcards because they can double as note cards, too.
If your local Wal-Mart has a photo lab with a HP poster maker, you can use a solid color template and add text without owning Photoshop or similar program. (The only photo files you'd need would be of your book cover and possibly a head shot.) With permission, you can have these posters displayed at libraries and also use them for book signings.
3) Being active in primarily two online communities (outside of Facebook & Twitter)
There is a balance between reaching out to people and spreading yourself so thin that you're not doing anything meaningful. I've gotten more out of being reasonably active here on Gather and on Writing.com compared to when I was trying to balance activity on about a dozen other sites. It's a lot more fun and less stressful, too.
4) Using Facebook and Twitter smartly and with other people in mind
I have friends that whenever they do a Facebook or Twitter post, it's only related to trying to get someone to buy their product or service--nothing more. This can get old very quickly, and that's even with knowing the person and product are good. It's one of those things that the same people would never do to you in real life but happens a lot in online marketing.
If used right, Facebook and Twitter are still great marketing tools. Facebook has an option of creating a public page for yourself or a business, and as an author it can be helpful to have this as a separation from your private life and friends. I follow the format of posting writing-related material to the public page then share it with my friends using the personal side of the account when I think it's relevant or important.
5) Develop an overall plan that's unique to you and your writing
This does take some time and trial-and-error. Depending on genre and primary audience, what works for one writer might not work for another and vice versa. The other aspect of this is the freedom to be authentic and not worry if you're doing everything exactly like other writers do.
Current project: My website
This could be a whole article in itself, and after I finish my current book I'm going to be focusing on developing it to the level I want it to be. As I do research for myself, I'm taking notes on anything helpful so I can pass things along, too.