Critical thinking is very important for children to develop their ways of thinking. As a teacher, you should teach your students about it. Critical thinking can be taught in any subject and the tips below will help you to deliver it in natural way.
You can start with re-arrange of seats position. You can make a circle so the students can face each other and understand that they have equal chance to ask or express their opinion about the topic. As the teacher, you will be not seen as preacher anymore because you also become the participant.