regular vaccuming/cleaning! i will also put some of the carpet powder down before i vaccuum sometimes-i usually use the ones that have baking soda or the ones for pets..they smell real good(well some of them

)
we have an air purifier too!!(love that thing!!) we use the airwick plug-ins..and also try and keep the windows open(for fresh air)when we can. Candles that smell real yummy-are good when people are coming over(i did that before i had Avie though too!

) and like Brooke said-we too use a steam cleaner on the carpets(only every few months though). Avery is potty trained-but sometimes she will get a little off the pad..so we make sure to clean that up asap and spray it.
everyones tips seem to be about the same.. lots of cleaning and yummy smelling things!! hehe.