Linking campaigns for a company

hey all,
i fully comprehend most of the techniques in SEO but what still confuses me is link building campaign. from all the seo books i read about being a competent seo freelancer is the importance of executing a link building campaign - inbound & outbounds.

but im confused on how seo freelancers perform link building campaigns for clients who are SMEs or big companies. Do you actually setup a page and list out links to reciprocate/exchange with the other party that you negotiate about exchanging links?

This is because i have never seen any link list pages (eg. wordpress blogrolls) on any corporate websites that i have browsed through. I feel having those pages publicly visible on a corporate website does not give a professional feel on it (my 2cents).

does seo freelancers actually ‘hide’ the link list page using .htaccess or folder locks? can Search engine still index and crawl them when they were hidden? (correct me). what is the right way of doing link buidling campaign for corporate companies who wanted to get a good & pure seo boost?