E-book marketing isn't anything particularly unique. It can be much like marketing a website or blog, or like marketing a physical product (if anything, it's like a combination of the two). When marketing your e-book(s), keep some of these marketing tools and tactics in mind:
Your Sales Letter / Sales Page
You have to have some kind of sales page that tells prospective buyers what they can expect, and that offers a way to place orders. That doesn't mean you have to use a long form sales letter that you'll see with a lot of e-books (although you certainly can). Your type of sales page should reflect your target market (create the sales page and copy in a way that it's most likely to appeal to your unique target group). Keep in mind that pretty much every other marketing tool and tactic will ultimately lead potential buyers to this page.
Your Blog / Website
A blog or website tied to your e-book can be an excellent marketing tool. The basic idea is that you use the site to provide current information, build a subscriber list, and solidify your reputation in the subject area of your e-book to build trust and make sales.
Affiliates are like your own little commission-based sales force. They do a lot of your marketing for you for a cut of the sale price. Most of the most recognized e-books have affiliate marketers behind them. If you decide to take part in affiliate marketing, make sure your price allows for you to offer them enough per sale to attract them in the first place (without overpricing to the point where no one will buy your e-book).
Write articles related to the subject of your e-book, and publish them to article directories, ezines, or niche sites with a brief sales pitch (in your resource box / byline area) and a link to your e-book sales page. Instead of writing unique articles, you can also opt to publish excerpts of your e-book.
Your opt-in subscriber list gives you a built-in audience for your e-book release. If they're targeted to the topic of the e-book, and you've used your list to build their trust in you and what you have to say in the niche, send an email notice, ad, etc. about your new e-book.
We'll talk about more specific e-book marketing tips and tactics during the 14-day e-book writing challenge (which starts tomorrow). In the meantime, if you're a past e-book author, what are some of your favorite ways to market e-books? (My favorite two methods are my blogs and forum postings.)