Here are five reasons why you should have a business blog for your books, writing, consulting, etc.:
Drive traffic to your website.
Get potential leads from that traffic.
Become an authority in your niche.
Connect with people interested in your books, products, or other services.
Set your books and services up for the long term.
Here are a few ways to market your blog (and, thus, your books, products, and services):
Write unique and creative content that is useful to your visitors.
Network with other bloggers and authors to build relationships.
Link to power bloggers and influential authors.
Comment on other key related blogs.
Respond to those who comment on your blog. Interact with visitors.
Continue to provide useful and timely content.
Focus on your brand (whether for you, for your book, or for your book series).
Humanize your voice across different channels (blog, video, podcast, and social networks).