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.
Free traffic, such as organic search engine visitors, video marketing, or social media/forum traffic, can be a great way to get highly relevant visitors to your website without paying for each visitor. Building a platform that delivers free traffic can be a great long-term affiliate marketing strategy. However, the downsides of free traffic are that it can take a lot of time and effort before you start seeing results, and can be unreliable.
ClickBank represents primarily digital or downloadable products. These typically have high-percentage payouts to affiliates. The commissions average around 50%. You do need to be careful and closely vet all products. There are some great products, some good products, and many crap products. You need to be sure the product and the promotional methods are appropriate for your audience. But ..