This is especially nice if you have sweet-smelling flowers or shrubs near the windows. Bring sweet-smelling cut flowers inside. Use incense or candles for scenting the rooms. Sprinkle baking soda or the scented version on carpets before vacuuming. Use a few drops of essential oil in your mop water.
Some favorites are lemon, orange and lavender.
Add a drop or two of essential oil to a load of laundry. Add opened bars of soap between you linens and clothing. Keep the sink drainer clean. Empty the trash can often. Keep the bathroom clean and the door closed.