Residual income could start with a membership site, if it has it's own affiliate program that you could join for free then like this one you could earn profits online recurring every month, a resource on affiliate marketing, see how it's done to build up an internet income.

Monthly Affiliate Membership

Earning From Online Business And Affiliate Marketing Activities With Online Business Branding

What about adsense as an earning revenue stream, a residual income method that keeps on paying by how much traffic you get to your blog or website and how you present and optimize your pages and posts, well branding does come into it, but your content shines throughout and leaves you looking like the expert that you are and so they click on the links in the adsense units.

Revenue From Adsense