Harvest them in late morning, when all the dew is dried up but they aren't tired from the heat of the sun. Hang them in a well-ventilated place out of the sunlight. As soon as they're dried store them in an air-tight container out of the light. My herbs tend to dry quickly since it's so dry in Montana. Over-drying can cause some of the medicinal constituents in the plants break down, so I don't let them hang for too long. Just to be sure they aren't still a little wet, which can cause mold, I usually open my jars after a couple days and leave the lid off for an afternoon or so. That way, any moisture that has sweat from the plants can dry up.