Choose a topic that you feel moderately about: favorite ice cream flavor, favorite Doctor, favorite Keats’ poem.
Have your protagonist defend it and your antagonist deride it.
Choose a topic that you feel strongly about: religion, politics, how you were raised. It’s part of your identity, your core beliefs.
Have your antagonist defend this tenant. Have your protagonist deride it.
Once you are done, look it over. How did your approach and your tactics change?
An author once suggested that, to avoid being heavy-handed about your strongest beliefs, have a foolish or a villainous character argue your point.