The proper dryer duct should vent directly outdoors—never to a room inside the house, as the air discharge can contain a combination of combustible gases.
Avoid plastic duct work, which is more easily ignited or melted; opt for a hard metal duct (with as few bends as possible) from the dryer to the exterior of your home. You'll breathe more easily when you load your laundry.
Keep the duct free of lint to help reduce the chance of fire spreading from the dryer to the vent. Clean the lint trap after every use. A professional should also help you periodically dismantle the dryer to clean between the dryer drum and the heat element.
Install a smoke detector nearby.