Seriously consider paying a professional proofreader. These are Goodreads, Facebook, Twitter, and Google Plus. Begin making friends. At this stage, it is acceptable to ask questions about your book, but avoid self-promotion. Amazon's own Kindle forum doesn't allow self-promotion. It's not moderated, and it can be a hostile place for independent writers.  Use an RSS aggregator such as Google Reader. This will allow you to check as many blogs as you like from one place. Post helpful, relevant comments on blog posts that interest you, always linking back to your own website. That may seem daunting, but something as simple as a PowerPoint presentation put to music can be very effective. Look at other authors' work for examples.

Summary:
Make sure that your book is as polished as possible. Join the major social networks. Join forums, introduce yourself, and begin chatting. Start a blog. Build a blog reading list. Consider preparing a trailer.