I am currently using several methods for building do-follow backlinks. The criteria given by my company is DR above 40, high traffic, relevant to niche. So I am currently building do-follow backlinks by guest posts, forum signatures, broken links, competitor backlinks, blog comments and skyscraper. I am told to build 60 do-follow links a month, which is a long stretch with the given criteria.
What is your advice on 1) whether the criteria should be flexible 2) whether 60 do-follow links per month is realistic, which I found to be hard and 3) any do-follow link building strategy I might be missing.