Always have a question on questions open

Construct a simple question:

What questions do you have?

Have this question always available for students to give their input in addition to the question or questions you have active on the student web page dealing with your current content.

You can quickly view responses to this question by toggling between the "eye" icons for multiple questions on the admin page.

Answers to this "question on questions" often generates the best insight on student understanding.