Money.
Content to make money.
Repeat.
See lightspeedcash for a example of the "right" direction to head in giving productive affiliates content to work with.
I myself am partial with a limited-dsitributed set of 15 or so pics per 10 signups you make, or something to that effect. Something where if I make you guys cash, you'll help me make you more since I've proven myself. I thrive with that.
But, that's my opinion.
-Phil