deadsea - 1:28 pm on Feb 17, 2011 (gmt 0)
Avoid making it obvious to your competitors that you are buying links. I was able to create a Google alert that told me about each new site in a network that my competitor was buying into. As soon as a link to my competitor pops up on a new site in this network, I report paid links to Google. When I do so I show that it is far more than my competition involved in buying links.
I believe that Google has penalized this link network now (but not my competitor). At least the competition isn't getting any more juice from the scheme.