"Fist to five" check students rate their understanding by holding up the appropriate number of fingers. The goal is for everyone to be in the green. Great way for students to self-assess their understanding and help you to gauge student understanding.
This is pretty student-centered and I think it is a good idea to take the student's thoughts into consideration when there are issues, like Caleb from Tough Young Teachers. Self-evaluation worksheet to help monitor and have classroom management.