Here's a list Jeff Vandermeer posted on Ecstatic Days; I've simplified it to fit any book, though you should go by and see his new books from FSG Originals as well. Jeff is one of those writers who is good at all the things writers have to do these days, including marketing.
Lady Word of Mouth
How You Can Help!
—Buy the book now.
–Buy the book during release week. Barnes and Noble. Indiebound. Powell's Books. Amazon.com, Amazon.ca, Amazon.uk. Indigo Chapters (Canada). Etc.
—Review the book. Blog, review site, or on social media. Any mention, especially noting whatever you really liked about the book, helps immensely.
—Review it on Amazon. Go to the Amazon sales page for the book and tell other readers what you liked about it. A quick and easy way to help get the word out and create interest.
—Make sure local booksellers carry it.
—Request it from your local library.
—Spread the word through twitter and facebook. Tell people about the book through social media, using your favorite link about the book.