All authors, whether trade- or self-pubbed, have to shoulder some of the publicity burden. How much you take on depends on the state of your finances, the amount of spare time you can scrape up, and also relies to some extent on your goals.
For example, if your book has a tight focus on a particular group (say, F1 enthusiasts) there's little point spamming writing groups up and down the internet. You'd be better off joining motor racing forums and joining in discussions, ensuring you have a carefully-crafted signature line.
I've looked at a bunch of different publicity options, including:
BookRooster reviews service
Sending out review copies
Blogging & author website updates
Approaching local stores
Offering guest blogs
Goodreads giveaways (print copies only)
Librarything Member giveaways (print or ebook)
Widgets and bookmarks
... and many more.
Why so many different places? Because most people don't pay any attention the first couple of times they see something mentioned, and you need those fleeting glimpses to add up over time. When it seems everyone is talking about a particular book, everyone DOES start talking about a particular book. We're odd like that.
So, what have I found? Straight-out advertising is the easiest way to get your book mentioned, but people know you (or your publisher) are paying for the privilege, so it's low on credibility.
The BookRooster service is an interesting one. There's a misconception that you're 'buying' positive reviews, but that's not the case. You pay your money, send in an epub copy of your work, and BookRooster makes it available to their members, all of whom have volunteered to read and review books. Your book is offered until it garners ten reviews, and BookRooster reviewers are instructed to post genuine, honest reviews.You might get ten one-star reviews, ten five-star, or (most likely) a mix. I've given it a shot with Hal Junior, and I'll let you know how it goes.
Sending out review copies can be time-consuming and expensive. Unless you're posting to the majors, you'll need to contact potential reviewers, offer your book, and wait for a response (and a mailing address). I contacted two or three dozen, after carefully checking their review policies to ensure my book was a match for their site. Only one third responded, although most of those agreed to receive a review copy.
Blogging about your book and posting updates to your website are good ideas, in theory, but if you don't have many visitors you're talking to an empty room. It's worth having an effective landing page for your book, with buy links, a cover shot and so on. Your blog will also receive visitors when people occasionally follow you back from other sites where you've left comments.
Approaching local stores is something all authors should do, whether trade- or self-published. There's nothing like hand-selling to drive your sales, and for self-pubbed authors it's handy to have a store where you can send buyers. (I rarely sell my own books. It's better to give the sale to a store.)
Offering guest blogs is an effective way to gain exposure. I've been blogging about the dearth of junior science fiction, the reasons I chose to self-publish my new series, the importance of editing and pro cover art with self-pubbed books, and so on.
I mentioned widgets and bookmarks, and in the past I've been known to commission all kinds of weird items to promote my books. In the end, though, I've decided that the best advert for your book is ... your book.
Yes, finally we come to the giveaways. When I was promoting my Hal Spacejock books a few years ago neither Goodreads or LT offered member giveaways, although Hal 4 was included in one of the very early LT Early Readers promos. It takes five minutes to set up a giveaway, and you can offer any number of books targeted to specific countries. LT Members Giveaway even allows you to offer ebook editions, which is basically free promotion.
Back in the day I used to offer signed copies of Hal Spacejock via my website, carefully collecting email addresses and mailing out lists of winners every month. LT and Goodreads have reduced this to a much simpler system, and Goodreads even selects the 'winners' based on whether they have similar titles in their libraries. Plus, the fact these winners are present on GR and LT increases your chances of a review.
To summarise this post, there are many ways to spend money trying to promote a novel. It's possible every dollar spent on promoting fiction is a total waste of money, but I like to play the long game. For example, I'm planning at least five books in the Hal Junior series, so raising awareness of the first should pay back later, when future titles are released and wavering buyers can see a bunch of reviews for the earlier books.
Simon Haynes is the author of the Hal Spacejock and Hal Junior series (Amazon / Smashwords / other formats)