Develop linkworthy content which is unique to your site.
Basically he sets up microsites that look well designed (it's usually a very simple single page design) and have relatively funny content aimed at the Digg community.
He then submits that content to Digg, pushes it, waits for it to frontpage and then changes the page to have a "sponsored by" or similar message at the footer or header, but so it looks like it's part of the actual original design.
He does this often (perhaps twice a month?) and the cost is very minimal to him, but sends several 10's of thousands of users to his main site and each of these microsites provides Google juice for his main site.
He has also managed to pickup additional traffic from bloggers looking for content via Digg.
Since your main target is teen-20something females, I'd probably start thinking up comedic microsites related to various celebrities? They always seem to be a fairly easy to hit target.
http://mingle2.com/dating/phases
You can also see some of the other microsites towards the footer of that page. They all usually changed after they frontpaged to promote his dating site. Classic bait and switch.
Here's a recent interview with him about marketing: http://blog.mixergy.com/real-marketing/
The Inman interview you linked to is full of techniques for marketing that doesn't cost money, but it does cost time.
My suggestion is to pick just one of his techniques and focusing on that (quizzes, shocking content, for example).