Start with your garbage and recycling containers. Take them outside and rinse them with vinegar and water. After they are dry, sprinkle baking soda in the bottom before putting in the bag.
Clean out your drain in the kitchen sink with a recipe from my book: The Joy of Green Cleaning. Start with two tablespoons of baking soda sprinkled down the drain, then heat up a cup of white vinegar and pour that down the drain. The mixture will foam. Let this sit while you warm up hot water in your tea pot. Once it is boiling, pour that down the drain to flush out anything that may leave a smell.
Mix up a bottle of half vinegar and half water with a teaspoon of borax and spray around the base of your toilets. Let the mixture sit for awhile and then wipe with a microfiber cloth. This prevents any smells coming from underneath the toilet.
Avoid decorating with cut pines unless you check with your guests first. Many people are finding they are allergic to real pine and may have a reaction while visiting you. Try to use the artificial stuff for your guest's sake. I'm using the real stuff to decorate the outside of my entryway.
If you have a pet, consider trying a new product called FreshWave. This product neutralizes smells instead of covering them up. You can use it as a spray or it comes in a jar that you just leave open in the room. The jar of gel will last you all the way through New Years if you open it now. It really is amazing how it works. And you home won't smell like your pet.