I hope this doesn't cause any offence by stating this in layman terms.
So you find a keyword with a high search count adn low competition using adwords. Register domains and build a site, work your ass off at getting the site listing as high as possible on search engines, then what?
a) sell a product you have sourced somewhere or an ebook?
b) offer free information and have paid advertising on the site?
c) direct link to a site that sells what the customer is searching for, (referral money)?
d) something else