Working as an author, especially a self-published one, requires being a jack-of-all-trades. You need to be able to promote, manage a website (which incorporates a lot in itself, i.e. design, seo, etc), write, establish connections, and the list goes on and on.
Articles are a great way to connect with readers and promote your writing. They’re also handy for establishing yourself as an expert in a particular field, and optimize your websites find-ability. Articles can be used to provide links to your site, increasing its SEO value in the eyes of King Google. If you don’t know what SEO is, here’s a handy article giving a basic explanation.
As a general premise for articles, Google loves articles 300-500 words long, a minimum of 250-300.
For every 100 words, mention your keyword 3-5 times. Doing so subtly to avoid breaking readability takes time, but it will improve your articles ranking in Google. Over doing it and stuffing your blog posts with keywords will actually shoot your page ranking down the drain. Try using the same words or exact phrases people will search.
Keywords should be grammatically correct with their usage. Incorrectly using keywords and jamming them everywhere possible will annoy both readers and search engines. Articles should read well, provide information with the least amount of marketing pitches for your book, website, etc, and focus more on providing good content for readers. Sound natural, talk as you would to one of your friends.
Hope this helps guys. Cheers!