Advertising in e-zines or newsletters can help drive traffic to your web site so you can improve your profits on your associate programs!
Do a search for "newsletter directories" (or a similar phrase) and look for newsletters that will reach your target audience. Make sure the newsletters you decide to advertise with have a large enough subscription base to make it worthwhile. Set up a separate landing page for each newsletter so you can track which ads bring you the best return on your money. On the landing page, repeat your advertisement line and mention the newsletter by name to welcome your visitors.