on Just Publishing Advice:
Blog commenting is the easiest way to promote your book for free
There are hundreds of ways to promote a book.
You can use free and paid book promotion sites, write a blog post every week and offer free books.
Marketing your book to find potential readers is a non-stop effort if you want to sell your book,
If you have published more than one title, you will know how much hard work is involved in keeping the buzz going for your books and ebooks.
Encouraging people to take an interest is not easy and is sometimes counterproductive.
Direct approaches using social media or even your email list often only achieve very low click-through rates, and poor conversions to book sales.
But when people accidentally stumble upon you without you coercing them, the results can be surprising. In SEO speak, it is called organic traffic.
The key element in obtaining this type of traffic is a shared interest.
In other words, they find you because you have expressed an idea or opinion that is interesting to them too.
NOTE from TSRA:
Never, Ever, include a link to your book, the book blurb, etc, in your comments to blog posts – let folks follow you back via your (fully detailed) Gravatar.