Purchase a hygrometer for your home. This portable instrument tells you how much humidity is in your home and how much humidity you need to add to the air. Place it in the area of your home that feels the driest. Keep it away from sources of direct heat such as registers and heaters. It will take two to three hours for the hygrometer to give you an accurate reading.
Purchase and set up a portable humidifier in the driest room of the house. Plug the unit in, fill the reservoir with water and turn the unit on. It will disperse moisture into the air. Refill the reservoir whenever it becomes empty.
Place bowls filled with water in different spots around your house. If the heating system is running, place bowls on the registers or on the radiators to help the water evaporate quicker.
Place houseplants in rooms around your home to help make humidity. Some of the water you give them will evaporate and the plants themselves make moisture in the air.
Use a clothes drying rack instead of the clothes dryer whenever you do laundry. Not only will this make humidity in the air, but it will also save you energy dollars.
Leave the bathroom door open during showers. Don't turn the ventilation fan on to remove excess moisture. Instead, place a fan in the doorway facing out to help move the moist air to other areas of the home.