Your home should have a fire extinguisher in the kitchen, garage, workshop, and utility room. The most versatile home-use extinguisher is rated A-B-C and is effective against many small, contained house fires. (The rating system is A, for fires based on ordinary sources such as paper and wood; B, for flammable liquids such as oil and grease; and C, for electrical fires.) If the extinguisher has a pressure gauge, check it monthly; if the pressure is too low, either have it recharged or replace it.
Fire extinguishers should be mounted on a wall where they're easily accessible and away from potential hazards such as the stove (so that you don't have to reach over a stove fire, for example, to grab the extinguisher). Many come with a wall-mounting bracket. To install, find a stud in the wall near the desired location. Using the bracket as a guide, mark the holes for the screws with a pencil. Drill pilot holes, and insert the screws through the bracket. Place the fire extinguisher in the bracket and snap the fastener closed.
All responsible individuals in the house should know how to use the extinguisher. The recommended technique is PASS: Pull the pin in the handle; Aim the nozzle at the base of the flames; Squeeze the trigger; and Sweep the extinguisher or nozzle from side to side, moving toward the fire. Once an extinguisher has been used, either recharge or replace it.
Use a fire extinguisher only if the fire is small, you have a clear exit in case the flames cannot be doused, everyone else is out of the house, and the fire department has been called. Never let the flames come between you and your escape route.