If your home tends to cool down at night after the sun sets, open the windows to bring in the fresh and cooler air. In the morning, as the sun rises and warms your home, shut the windows to trap the cooler air. Use this method in conjunction with other moisture-reducing practices. Very humid areas might still have high concentrations of humidity even during the evening.
Install a window air-conditioning unit. As it cools the air, it also pulls the moisture outside the home, hence the reason for the drips pouring out of the unit. The cooler air in the room will hold less moisture. Within a few hours of running the air-conditioning unit, you will feel the difference when you step outside. Of course, a central air-conditioning system will produce the same effect, but that is a much larger expense.
Maybe you have a basement that tends to have moist walls, contributing to the higher humidity levels in the house. Plug in a dehumidifier to pull moisture from the air and pour it down the drain. These units add heat to a room so they are not as efficient as a window air-conditioner in cooling and drying the air during the summer. If you have moisture problems during the winter, run the dehumidifier to dry out the air.
Exhaust fans pull moist air from rooms in the house such as the bathroom and kitchen where washing and cooking add water into your home through steam. Turn on the fans as soon as steam forms and only turn them off when there is no more steam in the air. Make sure the fans are connected to an outside vent instead of an attic where the moisture will still be in the house.