There are many methods of creating one way links like forum posting, blog commenting, social bookmarking, web 2.0, press release etc., please make sure any method you are using, do quality work as spam links don't work these days, only quality links would work, so be careful to it.
A one way link refers to a link that points to a web site or webpage. It is the single most important factor that search engines use to assess the ranking of a page in search results.
The one-way link is called a one way link because there is no reciprocation or trading involved. That is, the web page that was linked to does not contain a link back to the web page that linked to it.