The updated Lifehacker article is excellent, but I'm pretty much following its recommendations already. Unfortunately, the two tracking cookies mentioned in my original query have worked out ways to get around evasive efforts.
I'm still trying to find a (reasonably simple — ie, no script writing or similar ploys about which I don't know anything and am not going to delude myself into attempting) way to "kill" the ability of these cookies to be placed. That said, I've checked when they show up (ie, which sites seem to be the ones which place them) and they seem to be more innocuous than evil. So, unless and until I can find what I want, I'm not going to install stuff on spec (cf the final paragraph of the article).