"Conceptual understanding" is easy to say, but harder to define exactly or measure. Here are some effective practices.

You can't diagnose student misconceptions unless your questions truly exercise their conceptual thinking (instead of other skills such as memory or trained procedures).  This tool will help you quickly identify what methods will accomplish that effectively in your exercises.

https://www.courselets.org/chat/enrollcode/5bea01f43fef435dbb8680e3e1288652/