When trying to make money with an affiliate program, by all means pick a bigger niche that has more widespread appeal such as sports or horoscopes or kitchenware, rather than a narrow niche , such as surgical instruments.

This allows you to market the affiliate product anywhere, regardless of what the target audience may primarily be interested in.

Here is one of my favorites: www.horoscopes.ws the affiliate signup link is actually hiding at the bottom of the page. Everyone likes to look at their horoscopes. And the dollars add up, instead of the cents from adsense.

Educational affiliates are another hot area, since it has widespread appeal. But steer clear of specialized education, stick to more of grassroots stuff that the average joe is interested in, such as GED or SAT.