The best way to get referrals is to be honest. Don't try to sell FC as something it isn't. Let them know their earnings will be directly proportional to how much time they spend on the site, and that the potential to make money is neverending. For example, if you make them think they will immediately make 100's of dollars they may get discouraged when they get here and see that that isn't exactly how it works. If you let them know that FC is more of a place to get some spare money rather than a full income then they will know what to expect. Also, let them know that building a following here at FC helps increase earnings, but is not essential to making money.
Sell the positive points
--FC is FREE
--FC has a great reputation for paying consistently and on time
--FC supplies bonuses at least twice a week
--FC pays for simply posting in the forum
As long as you honestly represent the site referrals are more likely to stay active. Many of the people I have referred have decided FC isn't for them. I don't understand it, but maybe they feel like they can get more money for their time elsewhere which is fine, but trying to pretend FC is a get rich quick site will not help you recruit active referrals. Just my opinion!