Dave McClure Says Web Startups Must Tap Consumers’ Reptilian Psyche

Or you could just make something awesome and make it for yourself as the customer and stop needing tricks and strategies to keep people involved and "converting"

I see game mechanics, landing page optimization, and the like as compensations for not being remarkable in the first place.

Look at Threadless or Foodzie or even 37signals as models (certainly there are more) make your product remarkable first and then worry about refining metrics and conversions