There's probably no well-established playbook about how CIOs directly link technology projects and to the bottom line. For sure, it's not always possible.
But in today's business driven world, so-called IT projects tend are or should be driven by business initiatives. As a CIO once said, "there are no IT projects. There's just business projects of which IT is a part."
In other words, the discussion to adopt new technology does not begin with IT's role. Rather a business need must be established first. Technology is subservient to that need.