Socks need to match the dress pants rather than the shoes. For example, a navy suit and brown shoes should be worn with dark blue socks rather than brown socks. Charcoal suit and black shoes appear more stylish with dark gray socks.
It is important to note that the more formal the attire, the finer the socks.
When an overall outfit gets thicker in fabric, the socks should follow suit. This is why heavy fabric flannel suit or even tweed jackets look better with thick woolen socks that blend textures.
Just as with ties, patterned socks should not be worn with heavily patterned suits.
Patterned socks ought to be worn with plain suits or slightly subdued patterns.
But for sports coats, tweed or corduroy worn with chinos, you could wear socks that have similar check-like patterns.
