1. Start with the easiest clue anchors
In Darling in the FranXX mode the series clue is already spent, so your first job is to separate 5 characters, all listed for 2018. Gender is a blunt tool here (3 are male and 2 female), and pink hair appears on only 1 of them, while white covers 2.
2. Use contrast instead of repetition
Start from Zero Two, then change axis instead of staying inside the same visual group: dark eyes are the rarest tag at 1, and blue the most common at 3. Two guesses that share a hair colour burn a slot without narrowing anything.
3. Review the pool after each game
The overlap worth memorising is this: Hiro and Mitsuru agree on 4 of the five clue traits. In a pool of 5, that single pair decides most failed runs, so learn how the two differ before the next daily puzzle.