Updated July 2014
I've changed a lot of things since I posted this a couple years ago. Here's a list of what I'm doing now to promote a new release.
BEFORE RELEASE DAY
Before the release date I create buzz by getting my fans ready for the release. I give an approximate release date, release the first chapter of the book, create a banner teaser, post the book cover.
RELEASE DAY
New banner goes up. I post links for the book on Facebook, Twitter, my authors pages, etc. I create a blog post to announce the new book.
Once or twice a month I do a "Free Giveaway Sunday" on my Facebook page. If I have a new release out, I'll give away copies of the book one Sunday and things pertaining to the book during that month.
UPDATE
Don't forget to update all your other book pages when first publishing a new book.
For me this includes book sites Amazon, Barnes &Noble, Kobo, iBooks, Google Play, and Goodreads.
On my product pages, under the description, I always put "Also by Cheryl Bradshaw" and then the titles of my other books. It's great to show you are established with more than one title under your belt, and it's also a free way to promote yourself and let readers know the order of a series.
Add book to my page on Author Central.
I also update all blogs, websites, Facebook pages, etc. with the new book, links, banner, etc.
BOOKMARKS
I usually update my current bookmarks whenever a new book comes out. I use Print Runner. I sent bookmarks to fans, my street team, etc.
NEWSLETTER
I send out a newsletter every time I publish a new book or run a sale.
CREATE A PROMOTION/GIVEAWAY
I create a targeted Facebook ad for my new release, and I plan a BookBub ad as well. After the BB ad, I run ads on Free Kindle Books and Tips, BookBasset, BookSends, and eReader News Today.
WEBSITES/PROMO SITES TO UPDATE OR PROMO ON
Each time you publish a new book, there are certain sites you should be active on that you'll want to update with your latest release. Here's a list of sites I frequent:
Authors Den
You can create your own account and add your books. They have over 1 million hits on their site every month. You also can track your stats to see just how many people are looking at your individual profile and your book pages. All this is free. You can pay to upgrade/advertise.
Goodreads
Aside from adding your latest novel, you can and should run a giveaway. Information on that is also on the page I linked to above.
Digg.com
On Digg, you can submit a link to your new novel. I usually blog about it and then link to my blog. I use this site whenever I run a contest as well or am doing any type of donations.
Reddit works like Digg. You actually can just copy/paste what you submitted to Digg right into the form on Reddit.
I have a Pinterest account and an entire board dedicated to my books. To get an idea of what you can do with yours, you can see mine HERE.
Crimespace
On CrimeSpace, you can create an account and then blog or tweet from there about your book(s). This is a site primarily for crime/mystery/thriller writers only.
Library Thing Giveaway
On Library Thing, you can upload all your books from Amazon and also run giveaways through their authors promotions program. If you've never been on the site before, you can sign up and then find your books and select that you are the author. From there, it takes a day or two to get approved. Then you can list a giveaway and they accept both eBook and print, which is nice!
Authorgraph
With Authorgraph, you can add your books and be notified when an author wants an autograph for their book. They also feature different authors every month.
Google+
Google+ is a fast-growing way to share your information with others. You can create a profile, add your books, your links, etc. But what I like about it is that when someone searches you on Google, your profile comes up on the right, just like it does on Wikipedia.