Madison Woods asked this question and this is too long for a comment. So I turned it into a blog post. 
She also posted a poll with the following options:
1) I go to the bookstore and browse when I want a book.
I love browsing and I do this. I also go to libraries and browse the shelves there, too. Sometimes it works, sometimes not.
I rarely find new writers by browsing library and bookstore shelves. I suspect that’s because I head straight to the science fiction shelves. My local library’s science fiction section is smaller than almost every other section, but it’s still bigger than second nearest library.
The bookstore’s science fiction section is large enough, but trouble is, they usually only have authors I’ve heard of and books I know are out. Not books I’ve necessarily read, but books I am usually aware of.
Plus, the books (in both the library and bookstore) lean heavily toward fantasy instead of science fiction. Which, yeah, I love, but it’s not the best way to find new science fiction books to love.
I have better luck in romance. The romance section is always bigger and there are always books I’ve never seen before, authors I’ve never heard of. I’ve better luck in the YA section, too. It’s bigger, too. and I find plenty of books I’ve heard of, but also titles I’ve never seen before.
Maybe it’s just because those other sections are so much bigger. Maybe if the science fiction section in bookstores (and libraries) it would be easier to find new books this way.
2) I look through publisher catalogues to see what’s being published and choose from those.
I do this, too, but mostly for erotica publishers. They are mostly published as ebooks first anyway . . . So, yeah. I look at publishers like Ellora’s Cave, Loose Id, Samhain, Torquere and Amber Quill. Libraries and bookstores have books from them, but that’s rare.
I also look at some more mainstream publisher catalogs, like Tor and Baen. I got into the habit of checking Baen’s catalog because I used to go to their online library all the time. And Tor has a really great website, so it’s a natural step.
3) I buy editor’s picks or reviewer’s favorites (which editors or reviewers are your favorites?).
Oh, I get NYT book reviews in my email and I even read them sometimes. Lately, I’ve been reading reviews that show up in magazines like The Magazine of Fantasy and Science Fiction. There are some specific review sites I visit every so often, like Rainbow Reviews and Dear Author.
But I like blogger reviews. 😉 The bulk of the reviews I read show up in my Google reader, written by the bloggers I follow. This is how I discover a lot of new titles and authors.
If the book sounds interesting, I will read an excerpt of the book and maybe after that I’ll get the book itself.
4) I buy books being promoted on Twitter.
Sometimes. Not very often. Haven’t really thought about it, but I think the links I do click on are from people I like/trust and don’t spam me.
More often, what happens is, people talk about a book. They mention a title in random conversations or during the specific twitter chats like litchat and I’ll think, that sounds interesting.
5) I buy books promoted on FaceBook.
Not really. But that’s because I don’t spend much time on FB.
6) I buy books from writer-friends.
Yes.
7) I buy books because I’ve enjoyed the author’s blog.
Rarely. I find author blogs/sites because I enjoyed the book and looked up the site after the fact. Or I discover a title somehow and want more information.
8) Suggestions from friends.
This would be true, but most of my real life friends don’t read. Or they don’t read the kinds of things I enjoy. Which basically means I stay away from whatever they are reading. (A lesson learned from attempting to read books she enjoyed.)
9) Other
Other ways I find books is Amazon. They give me titles other customers looked at and/or bought like the one I am looking at. Or they suggest titles based on my browsing history. It’s a little limited, because the titles can be very niche specific. Lots of times they list nothing but other titles by the same author. But it’s still useful.
Also, the meme teaser Tuesday. Sometimes I read really interesting quotes and than I go looking for reviews. Sometimes a book shows up over and over and over again and than I have to find out why so many are reading it.
Also, LibraryThing and Goodreads both regularly give away ARCs and sometimes the titles look really really interesting. I have discovered some new authors that way, too.
Loud people, all the pushing and shoving. She wished she didn’t need to buy gel right now. She wanted to avoid the insanity of Black Friday.
Home didn’t look like home anymore.
I read online Anne McCaffrey might have passed away and my reaction was: please don’t let her be dead.
“Grandbaby is so big now.”
He paused. Stared at the cup of coffee someone had left.
Story Treasury 