It all depends if you have a washerless type faucet or a washer type. If you have a washer type you not only should replace the washers ASAP but the valve seats to prevent any more water waste and possible erosion or the shower body itself.. If it is a washerless type get the name of the manufacturer and they will send you a diagram of how to repair. OR go to any plumbing supply with the name of your shower body. The name is sometimes on the handles