When making fires it is important to make sure that they are under control. This means that you should always have at least one method of putting out a fire. The ways to do this can be thought of as the opposite of how to start a fire. Since a fire needs heat, fuel, and oxygen, you need to take them away.
Best ways to counter aspects of a fire:
Heat: heat can be dissipated through several materials but most commonly water and fire extinguishing foam.
Fuel: fuel can become unusable by wetting it however this is the hardest to take away because it can catch other things on fire.
Oxygen: the most common ways to stop oxygen flow are smothering it with a solid object, or smothering it with water or fire extinguisher foam.
All of these will work to varying degrees, although good choices for wood burning fires are water or fire extinguisher foam because of their heat dissipating and smothering ability. It is always important to keep some form of these near a fire in case they are needed to put it out.
Water is only effective on fires that have started because of wood. Electrical and grease/oil fires can be strengthened by water and so water should never be used to put out those types of fires.
Fire extinguishers can be made to put out all types of fires. To find out what types of fires your fire extinguisher will put out, you will need to look for the symbol on the label. This is a helpful table from Fire Extinguishers – Grainger Industrial Supply.