To fix a leaking faucet, you should first turn off the water supply to the faucet. Then, remove the handle and the nut that holds the stem in place. Next, pull out the stem and replace the washer at the bottom. Reassemble the faucet and turn the water supply back on. Check to make sure the leak has stopped. If these steps are too complicated for you, you may need to call a professional plumbing service.