What colors match for interconnects?

When I'm matching up interconnects with components, there is a strange little conundrum I sometimes encounter. The three colors; white, black & red. Or sometimes no colors, just left or right. Is there some simple rule of thumb for always selecting the right color or side? For example, is white, or left, always hot(pos)? What if your RCA posts are red & white, but your cables red & black?