Odor: Now is a good time to wash out all of your trash and garbage cans, especially in the kitchen.
Dust: Change your furnace filter, for one. And take a Saturday morning to get those out of the way places where dust builds up: behind the fridge (and on top), on top of kitchen countertops, couch cushions and under the couch, and closet floors for example.
That'll give you a good start to a fresher home environment in the coming months.