Many interior paint, stain and stripper fumes aren't just harmful to inhale, they can also be extremely flammable. You should always keep the area well ventilated by opening doors and windows. Use an exhaust fan to remove fumes from your workspace. Never paint or use solvents, strippers, stain, caulking or clean-up supplies near an open flame like the pilot light of a furnace or water heater. And never smoke while painting!
When working with solvent-based materials, it’s best to wear a respirator to prevent inhaling harmful fumes. When sanding, you should wear a dust mask to prevent particles from entering the lungs. If possible, use a power sander with a sawdust collection bag.
If you can avoid it, don't sleep in a freshly painted room for at least two days.
Use canvas drop cloths instead of plastic on the floor. Cloth stays in place better and is less slippery than the alternative.