If you're serious about making money online, start a blog. Blogging is one of the easiest and most sustainable income sources. As long as the blog is setup the right way, in the right niche, with the right content targeted at the right audience, and the offer is complementary to the content, you could make a tremendous amount of passive income from a blog.
Once you have the affiliate links you need, it is time to present them to your audience. As you start using affiliate marketing to talk about products, you need to be aware of how your audience perceives you. If your website appears to be only after their money through an overwhelming amount of affiliate links, then they are more likely to simply leave your site.