1. Start with the easiest clue anchors
In Gintama mode the series clue is already spent, so your first job is to separate 5 characters, all listed for 2006. Gender is a blunt tool here (4 are male and 1 female), and white hair appears on only 1 of them, while black covers 3.
2. Use contrast instead of repetition
Start from Gintoki Sakata, then change axis instead of staying inside the same visual group: red eyes are the rarest tag at 1, and blue the most common at 2. 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: Kotaro Katsura and Shinpachi Shimura 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.