1. Shut the water off. You will need to turn the water off to your faucet. Check under The  sink for the pipes that run  to your faucet.   Somewhere along the route of those pipes  will be handles (See First Picture) turn this valve to shut the water off to your sink.
  2. Turn the handles to the right clockwise to shut off the water.  Turn the handle right to shut off.Remember  “Righty-tighty, lefty-loosey”.If by some chance there is no shut off you will need to shut off your main water supply which is located near your water meter. 
    Fig. 1
    Stop up up the sink drainafter you have turned off the water. Use either the stopper on your sink for plugging the drain, or do it yourself with a rag. You dont want anything to go down the drain, more trouble.
  3. Take the faucet handles off. Take out the screw Picture (2) that is holding them on. Use the screwdriver for this. Some faucet handles might hide their screws behind plastic or metal caps. You might have to pry the cap off with a flathead screwdriver to get at the screws holding the handles on, or unscrew a cap. Once you’ve removed the screws, pry the handles off with a flathead screwdriver. Some handles might come off easily without the need for prying.
    Fig. 2

    Picture 2

  4. Once you have the faucet handle off (Fig. 3), remove the old washer that was behind the handle. If there is no washer behind the handle, that is okay, you are going to add one.
  5. Take the washer you’ve purchased. Simply place the washer where the old washer was. (Fig. 4) Basically the hole in the washer should be just slightly bigger than the post that the handle turns.
    Fig. 3

    Fig. 3

    Fig. 4

    Fig. 4

  6. Put the faucet handle back on the post and put the screw back in. Tighten the handle until it is “hand tight”. That means tighten the screw until it feels tight without you having to use extra strength to tighten it.
  7. Turn your water back on by turning the handles under the sink counter-clockwise (remember, “Righty-tighty, lefty-loosey”).
  8. Check it. If everything went well you shouldn’t have a leaky faucet any longer. If your faucet continues to leak, try tightening the screws on the faucet handles just a bit more. If the faucet still leaks, then it really is time to call a plumber.