[jordanchan]

The US Gov has a very nice little book on the topic - A Tradecraft Primer: Structured Analytic Techniques for Improving Intelligence Analysis. Just google and you'll find it on the CIA's website.

The book is geared towards the intelligence community but can be appreciated by all intelligent communities, especially on a topic such as this *. In a nutshell, it is about discovering implicit assumptions, questioning them, and checking for alternative explanations - in all areas of analysis/thought.