I DoW the closest civ to me as soon as I can move in and start taking workers without losing my own units, and stay farming workers until I have as many as cities I plan to found (usually 4, dat Tradition). Sometimes it takes longer than others. If I'm getting archers out while I'm still at war I'll send them over to get some xp. Oddly enough I find that once I make peace the civ I DoWed, as well as others, are instantly friendly and often even DoF a turn or two later. This holds particularly true for warmongering civs, almost as if they respect me for showing some balls or something.
My favorite answer though was "if my computer is on."