Here are a few basic things...
- Update your paysites and make sure affiliates know the sites update.
- Provide fresh promo material regularly for affiliates.
- Have a resource page and exchange links with resource sites, lists and other programs/companies.
- Submit press releases to news sites.
- Be active in the q&a forums, it's a great way to build trust.
- Contact your currently affiliates directly to see if you can help out.
- Direct contact new affiliates that match your niches.
- Be cool, be helpful and respond to questions quickly.