Place a dehumidifier in the areas with the most wall condensation. If you have several areas, particularly on separate floors, place a dehumidifier on each floor.
Install an exhaust fan in your bathroom. A true exhaust fan vents the warm and moist air from the bathroom outside, and does not simply recirculate it into the house. Have a licensed contractor or electrician install the exhaust fan.
Examine the exhaust fan above your stove or range. Notice if the fan vent goes up through the ceiling to vent the warm air outside, or if it simply blows it back out into the kitchen. If the vent does not lead outside, call a contractor to have him install a vent that does.
Spray the outside walls of your home with a sealant that will help maintain a vapor barrier. The sealant will insulate the inner walls, and will prevent moisture from accumulating inside your home. This is particularly useful on the outer walls surrounding a basement.
Install storm windows in the walls where the most moisture forms. This will prevent the windows from sweating and having moisture streak down the walls.