Single generic web form - not prompted if cookie'd?

We are looking to set up a single generic web form that a new site visitor - trying to access specific high-value web content - would be prompted to complete only once and then afterwards, since they were cookie'd, they could access any of the site's content without being prompted again to complete a form. Also, a returning (cookie'd) site visitor wouldn't be prompted at all then to access [gated] site content, etc... 
Is there a resource where I can see how to set this up via Marketo or can any describe how to accomplish? Thank you!