Critical thinking is a habit, and to help your students develop that habit, assignments can be helpful which require them to look and listen in their own world for the kinds of thinking all around them.
Provide the students with a list of important critical thinking terms, briefly defined. Hare's 2004 "glossary of open-minded inquiry" is an excellent example, but if you do not have access to it, then you can use the vocabulary and definitions we have employed in these modules:
Require students to look and listen throughout a week for examples of behavior that they recognize from the list, and ideally even someone using these words in daily language.
Either commit class time to discussing the experience, or require students to journal about it in a reflection notebook. In either format, you can give the students some reflective prompts like "When you saw or heard these critical thinking terms in the wild: (1) Were they used correctly? (2) Were they effective? (3) How could they have been used better or differently?"
Hare, W. (2004). Open-minded inquiry: A glossary of key concepts. Inquiry: Critical thinking across the disciplines, 23(3), 37-41.