How Can I Stop Mixing Up Fundamental Rights and Directive Principles in UPSC Prelims?

I understand the basic distinction between Fundamental Rights and Directive Principles, but UPSC prelims statements often blur the two by testing their purpose, enforceability, or relationship with the Constitution. I keep second-guessing questions that use close wording.

What comparison method or revision approach has helped you separate Fundamental Rights and Directive Principles under exam pressure? I’m especially interested in ways to avoid memorizing isolated facts without understanding the distinctions.