Turn off the water supply under the sink
Close the drain or place a stopper in the sink
Remove the faucet handle
Take out the retaining screw or cap
Remove the cartridge, stem, or valve assembly
Inspect washers, O-rings, seals, and cartridges for wear or damage
Replace any worn or damaged parts with matching new parts
Clean mineral buildup from faucet components
Reassemble the faucet
Turn the water supply back on
Test the faucet for leaks
Tighten connections if needed
Replace the entire faucet if repairs do not stop the leak