The absolute easiest way to make money from a local (or niche) directory? It's NOT featured listings. (although they can certainly help) Instead, turning your directory into a MARKETPLACE style site, with joint venture opportunities (JV deals) and using your SHOP to sell affiliate offers (those being offered by your members, with YOU as an affiliate) is a super simple and phenomenally attractive way to not only get high quality members, but to create a win/win community where everyone comes out on top. (including the public who will get deals/coupons/products/offers from your shop that are related to the listings found on your directory)
The OTHER best is selling HIGH end agency offers. Period. You need a big back end to turn directories into a profitable, high end business...and the above video demonstrates a quick and easy way to sell both (affiliate/jv deals AND a very basic "agency" offer that has real value - in this case, actually SETTING up the affiliate program for your clients so they can participate with products/events/offers on your site) Make sense? Feel free to ask if anything is unclear!