Turn off the water supply under the sink
Open the faucet to release any remaining water
Plug the drain to prevent small parts from falling in
Remove the faucet handle
Take out the retaining nut or cartridge clip
Remove the cartridge, stem, or valve assembly
Inspect washers, O-rings, seals, and cartridge parts for wear or damage
Replace any worn or damaged parts
Clean mineral buildup from internal faucet parts
Reassemble the faucet in the reverse order
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