It seems like so many different things are hyped as the one definite way for people to learn about a new book. Some of those are actually old, but have cycled around to become the hot new thing.
Book trailer videos - good if you have the skill, but if you don't... well... I looked at a few when the fad first started and knew right away I didn't have the skill level for any of it - art, audio, pacing.. What has been your opinion on this?
Reviews
When my first book came out, reviews were what you had to focus on. At that time there were numerous book review sites, all looking for new books to review. Some of them are still out there, but finding them has become difficult. And if you can't find the sites, how many readers are actually following them? My old publisher and my new publisher were good at sending books out to their lists of reviewers, but they also want their authors to get reviews.
Places like Amazon and GoodReads are fussy about what reviews they accept. (are you friends with the author, did you buy the book from Amazon...)
Book Announcements
When I consider myself how I find out about new books, I realize how much I'm probably missing. I follow Shelf Awareness, though actually it turns up in my email, because I supported an independent bookstore which has since closed. Looking at their submission guidelines, they don't want ebooks or those without national distribution, so that limits them.
For science fiction books I check Locus. They have several review sections, but also a big section on "Books Received", which I actually pay more attention to than their reviews. I've had my books appear in the "Books Received" section as it's easy to send them a copy. I've noticed a slight bump in sales after an announcement there. There's also a remote possibility that a book they receive might be selected for a review.
And, of course, never forget to send a book announcement to your local paper, university newspages, Facebook Author page, or other such sources.
Book Listings
I recommend that authors set up their own author page on Author Central on Amazon. It helps readers find your books from various publishers and gives you an idea of how sales are doing through Amazon. B&N used to have author pages, but I can't find any links to them now.
GoodReads is another important place to have your author profile set up and your books listed. I'm lucky in that some of my publishers make sure new books are listed quickly. Unfortunately I also have a few publishers with multi-author publications that forget to have all the authors listed for a book, which makes it a bit difficult to add to the author profile. Make sure to check on your author profile so that any books written by an author with a similar name don't turn up there. There are helpful people at GoodReads who will correct the problem when you alert them (too many Kathryn Sullivans write books).
If you're a YA or children's book author, YA Books Central, is another spot to consider listing your books. They also review books. (And if you write reviews, you can sign up to be a reviewer).
Blogs
I've been told that blogs are dwindling in popularity. I still follow several myself, and you're reading this here, so I guess you do, too. I still hear from authors setting up blog tours or asking for blogs willing to sponsor guest posts.
Jane Friedman recently wrote a very helpful blogging for writers, where she covered content, frequency, whether to have your own blog or share one with other authors (hello, YA Authors You Never Heard Of) and several other topics.
Interviews
Newspapers and radio stations are still good for interviews, but podcasts like Writer Groupie are looking for people with stories to tell.
Contests
I've posted about awards before, but there's been news about a recent scam contest put on by a fake literary magazine. There are still good contests out there, like the EPIC eBook Awards, and an author should check sites like Writer Beware and evaluate before submitting.
Ongoing Promotion
Don't think that promotion is "one time and done". And yet you don't want to be "one of those" authors on Facebook whose constant refrain is "buy my book, buy my book, buy my book". Consider more subtle means of promotion, like swag on freebie tables at conventions, pens or bookmarks you can hand out. I even have a little sticker I put on the back of envelopes I mail. Not sure if any of the companies I pay bills to notice a sticker about my books, but it's there.
Fellow authors are also sometimes willing to give others a boost. John Scalzi often has a Christmas guide where one day is devoted to indie authors to list their books. File770 not only sometimes has announcements about new science fiction and fantasy books, but people posting in the comments (one of the few places where you want to read the comments) also recommend books.
I set up my Facebook Author page awhile back. Some authors set up separate pages for each book, which to me seems overkill. Having an author page separate from my own FB page though, allows me to talk about different things. I also have a Google Plus page, though I don't post there as often. I know other authors have a Tumblr page and Twitter accounts. Which do you feel works better for you?
What other means of getting the word out about your books works for you? What do you notice as a reader?
In picture books, my favorite was not a book but an author/illustrator, 
