I've been asked many times how I find information on the Web so effectively. I've always had a hard time answering that, because my efficacy at searching the Web springs from many years of experience with online networks (starting in the Israeli versions of FidoNET), from accumulated observations, and from sheer instinct.
I do try to offer some basic tips, such as examining the URL, looking for telltale signs of commercial or other interests, etc., but I never have time to give a comprehensive answer. So, since some of those who asked are likely to read these words, I refer you to a very decent page explaining the basic heuristics of evaluating Web pages, from the librarians at UC Berkeley.
It is no doubt basic for all you experienced Web ferrets out there, but for the sake of those who might benefit, there it is.