Turn off the water supply to the faucet
Plug the sink drain
Remove the faucet handle
Take out the retaining nut or screw
Remove the cartridge, stem, or valve assembly
Inspect the washer, O-ring, and seals
Replace any worn or damaged parts
Clean mineral buildup from the faucet parts
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