One of the first steps every author should take is the construction of an "Official Author Website". There are tons of businesses out there hungry for your dollars that will do a great job of building you a website. If you have some free time and want to save the cost of the website to spend on gifts for friends, or to spend on marketing that next great novel you're writing the process of building your own site is relatively easy once you've mastered the website tool. For my "The Official Website of Bryan Koepke" I used Go Daddy. There are lots of other choices out there, and as someone that used to build websites for friends back in the early 1990's the Go Daddy tool seems clunky at best. That said a little time looking at the sites of other authors on the web will fill your mind with ideas and make the task much easier.
Facebook - It seems everyone whether traditionally published or self published has their own Facebook page these days. The set up is easy and lends itself to uploading the banner image from the cover of your book or you author platform.
Twitter - While I myself am fairly new to the concept of Tweeting I've got to say I love it. 140 characters - what's not to love. I still haven't figured out the algorithms they use to attract followers to your tweets or to the tweets you read, but at this point I'm sold.
The biggest step you can take to get more publicity is to write your next book. It's been said time and again write another book. When I look at an author on Amazon, more times than not, the biggest thing that interests me is if the author has a slew of books to choose from.
Get reviews and don't pay for them. Much has been said and written on this topic as of late. Most of us judge a book by what other readers have had to say about it. To accurately review a book you must first read the entire piece from cover to cover. It takes an investment in time, and a choice to read and review a book.