There are ebooks on how to market ebooks, google around.
SEO-wise, review your book content and decide 1) what demand does it specifically fill, and 2) what are the best niche keywords associated with that demand. Double check with some keyword search tools, build the minisite/blog/lens and articles around the keywords, and link the site to your sales or presell page. You could premiere it as a WSO to test how popular it will be and to gain testimonials. Project how many sales you want/month, then do a test PPC campaign to see what the real world conversion rate is. BH-wise, look over the tactics suggested in the make money section, try out the ones that appeal to you.