Have your carpets professionally cleaned.
Hang an odor-absorbing product near the source of the odor or where your pet spends much of his time.
Wash your pet's bedding more frequently, or buy a new cover for your pet's bed.
Install an automatic aerosol dispensing system that freshens the air with a scent of your choice at the interval you choose.
Clean up any "accidents" as soon as possible, and use a product such as OdorLogic® CleanAway that removes odors organically instead of just covering up the odor with a pleasant scent.