Charcoal suit with charcoal knit tie and cotton square to match shirt.The Smallest Thing Makes the Biggest impact.
Love the grey on grey for suit, tie and square. Then color in the shirt. Maybe a larger pattern. Gingham only if multi-color.
The GQ Guide to Suits: Christoph Waltz
55 style rules very helpful
Mads Mikkelsen in the New Brown Suit
Pocket squares for well mannered rebels @gq Magazine