Ventilation is the key, as you want to get that moist air out of there as quickly as possible. So leave as many vents and doors open as you canespecially those high on the tentand try to point the tent so prevailing breezes can blow through it. Of course, the tradeoff is whether you'll be comfortable temperature-wise. On a cold, windy day or night, though, condensation isn't really an issue, so button things up.
I find the problem to be worst on very still, cool nights, when the temps are around 35 to 40 degrees and the air is dry. Fall camping, in particular, seems to lend itself to condensation issues. Of course, the more people you have in a tent, the more apt you are to have condensation.
That said, most tents I've used in recent years deal with the problem fairly well. Some makers are even making tents with a single, non-breathable wall, in theory a sure formula for condensation. But good ventilation design mitigates the problem remarkably well. It's often helpful to leave your tent out in the morning sun to dry, but that's just the nature of the beast. Condensation is often, plainly and simply, unavoidable.