almost never go lighter than the pant.
if contrasting the pant, match the shirt or compliment the shirt.
patterned socks should not take attention away from the shirt or pant.
solids are easy, but also boring.
shoe color shouldn't affect sock color unless you're wearing a crazy-colored leather pair of shoes. However, if shoes are black, I usually stick with black socks or dark colors.
best of luck, go beards and handsome emaws.