Given a DP problem, ask: (1) Is it interval DP or layered DP? (2) Does the cost function satisfy QI? (3) Are optimal splits bounded? Interval DP with QI → Knuth.
Layered DP with QI → D&C. Neither → standard DP or different improvement. Practice problems: Matrix Chain (Knuth), Ciel and Gondola (D&C), Optimal BST (Knuth), Printing Neatly (D&C). Build intuition by solving 5-10 problems. The pattern recognition becomes automatic.