How can I fix a leaky bathroom sink faucet?

To fix a leaky bathroom sink faucet, you can start by turning off the water supply to the faucet. Then, disassemble the faucet handle and replace the worn-out parts such as the O-rings or washers. Reassemble the faucet and turn the water supply back on to check for leaks. If the problem persists, you may need to replace the entire faucet.