Start staying in ,

Cooking, baking extensively!

You could start cleaning the floor with some perfumed solution

Place a few glasses,filled with vinegar,throughout the house,for the next 24 hours! You will be amazed at the difference this $2.00 fix will make. Be sure to wipe-down the bathroom walls with a vinegar reduction as well. Rinsing is not neccessary!

A good thorough cleaning should help. you might need to paint the walls. I would use a good primer like Kilz first. Try cleaning with vinegar or ammonia based products. Obviously, any drapes should be professionally cleaned.

Change the door locks including the automatic garage opener!

Oust newest spray air and surface in unscented. Spray on doorknobs, windows use Windex.

Open chimney chute for backdraft, sucks air out of the house.
Cold air might blow in also.

Mop the floor with a smell you like and pass a a wet rag through your walls with that liquid of your choice.

I would just take out all the furniture, curtains, etc. Then spray the whole house down with febreze and have it thoroughly cleaned. Spray all the furniture and curtains with febreze also.

Febreeze! It may be caught in soft furnishings if there are any left from the previous owners. Also, wallpaper is like a sponge, so strip it off!

Try using some Air freshener,like the ones you plug into the wall! (:

Febreeze, i prefer the one with the purple cap, lavender something.