Grey sneakers offer versatility in shirt color choices, allowing for a wide range of options except for tans or browns. While there are no strict rules, it's generally recommended to coordinate colors without being overly matchy. For khaki pants, pairing them with a blue or burgundy shirt creates a nice contrast. It's also advised that shoes should match the belt, particularly when wearing dressier pants. The overall look should prioritize comfort and personal style, and while some suggest sticking to neutral tones, others emphasize the importance of color degree and personal expression. Ultimately, the key is to wear what feels right and harmonizes with one's personality.