For casual outfits, like khakis, chinos, or jeans, you'll want to make sure to wear a complimentary color from the same color family. You have a bit more flexibility, but we still do not recommend wearing brown shoes with a black belt. We also like to keep belt material and finish more casual. For more unusual color shoes, we recommend: anything in the gray and red family we'd pair with a black belt and anything in blues and greens, go the brown route.