Pry off the cap of the faucet with the end of your screwdriver. Remove the screw that holds the handle in place. Pull the handle off the cartridge beneath.
Pull the stop tube fitted over the cartridge off by hand.
Pull the handle washer off the cartridge.
Lift the retaining clip that fits into the cartridge, on the top, up and out with the end of your screwdriver.
Pull on the cartridge with a pair of pliers, wiggling gently to remove it from the valve behind.
Clean the inside of the valve with soap and water to remove any dirt or debris.
Insert the new cartridge and reassemble the unit.