Arrange your clothes dryer so that it vents inside your home rather than outside the home. That strategy is especially helpful in winter, adding both heat and moisture to the air in your home.
Dry clothes on clothes racks or hangers inside your home. Air drying clothes inside allows the moisture in the damp clothes to evaporate into the air.
Place potted plants throughout your house, and keep them watered well. The plants will add moisture to the air.
Cook on top of the stove instead of using the oven whenever possible. Cooking on the stove top allows moisture in food to evaporate into the air.
Boil pots of water uncovered when cooking on your stove. The steam will evaporate, adding humidity to the air.
Place buckets of water in your home. As the water evaporates, the air's humidity will increase.
Keep the bathroom fan off when showering. Doing so retains steam created by the shower, which helps to increase the air's humidity.
Purchase a humidifier to add moisture mechanically to your home's air.