If you want to grab a small piece of the market you need to highlight a unique or new product that is not installed in the search engines yet. Of course getting to the point were you can market like that requires tons of SEO to bring the saturation of your site up to an acceptable level.
I still got tons of SEO to do, but say I have a PR6 and I'm getting some organic hits then that's when I start my marketing campaign. First research, CNET, BBC Technology, and other sites that offer product news or new products or upcoming product, add that product to the site with an affiliate link attached. As an example Buy.com allows you to make your own link. Say I was in a position to do that when the new iPod hit the market, traffic would pour in! It works until the large sites saturate search engines.
There is tons of SEO before one can effectively implement such a plan, but if you use this tactic you will make conversions! Its what called organic search engine marketing for affiliate programs. That is the one way you will compete organically.
And if you develop a site with some visual appeal people will like it and bookmark it. Make a site that puts them at ease visually. Use mild colors and round off the hard corners, put some fun graphics on the site. Your site should say "Come on in sit down stay awhile have a beer". "Lets talk computers or movies whatever". Oops I spilled my beer, but your customer does not mind because he or she is at ease with the surroundings. When you customer wants to leave, you walk them to the door and say "come again you are always welcome".