How to Do Your Case Study
Third Edition
Critical thinking
Critical thinking at the University of Sussex
Critical thinking at the Open University
Most universities have their own webpages for helping think about critical thinking. These two are from the University of Sussex and the Open University.
This, from the Stanford Encyclopedia of Philosophy is as good a discussion of critical thinking as I have found anywhere. It places critical thinking in a philosophical context, linking it in particular with the philosophy of John Dewey.
This, from the Foundation for Critical Thinking, gives an excellent definition and covers all the bases, with sections on