When you are driving someplace you have the belief that you will get there safely.
An effective driving strategy is contemplating the things that prevent you from getting to your destination safely. What if a deer runs on the road? What if an oncoming car swerves into your lane? What if you have mechanical troubles? Contemplating these beliefs that are opposed to your belief of arriving safely, helps to solidify your belief of arriving safely.
I believe the same idea can be applied to all your beliefs.
I make it a practice to put myself in someone else’s beliefs and genuinely try to see and defend the belief from their perspective.
Out of this practice, there are only two possible results. One, my belief is strengthened by having a deeper understanding of other beliefs. Two, I may change my belief because the new belief has better more sound arguments and supporting facts.
Either way, I am better off.