There are many different types of teaching situations, stances on the preliminary issues, types of students, kinds of teachers, and types of situations. Each teaching situation is unique. So there are no universal hard-and-fast rules. I recommend careful consideration of the advice under the label, "Twenty-One Strategies and Tactics for Teaching Critical Thinking", deviating from it where appropriate, being sensitive to the needs and backgrounds of your students and to other factors in the situation, making full use of your experience, using and developing your background knowledge, and striving for sufficient understanding of the situation. Think critically about teaching critical thinking.
See also "Incorporating Critical Thinking in a Curriculum" for a discussion of some of the broader problems in teaching critical thinking.