Warfare
Weaponry
Soldiers were equipped with a variety of weaponry, including the grenade, at right. In a way, the grenade was the primary weapon of the infantry. It enabled a soldier to engage the enemy indirectly, but without a need for precision. The hand grenade is an old weapon, but had gone out of vogue by the First World War. The armies found that the hand grenade was suited for trench combat, and the grenade found a place on the battlefield again. Some grenades were home made, and called "Jam Pots." They were sometimes made from old tin cans.
The machine gun was another weapon of trench warfare, and, often, the weapon we imagine when thinking of World War I. Combined with hand grenades, they ended the strategy of thoughtlessly charging the enemy, and the use of calvary on the battlefield. Assaulting the enemy became much more difficult as a result of these weapons.
Although not necessarily thought of as weaponry, barbed wire was an important part of trench warfare. It slowed the enemy in crossing the battlefield, and was an important defensive measure. They made the enemy much easier to cut down with machine guns and explosives.
Gas Attacks
The First World War is often marked as one of the first instances of chemical warfare. On April 22, 1915, the Germany Army used chlorine gas at the Battle of Ypres. Although very few people died, the news of this started widespread panic, and gas masks became a common part of the soldier's equipment. Both sides of the war used gas as a weapon; although it was not always safe: when the wind changed direction, gas could be against you!
There are three main types of poison gas used in the Great War: Chlorine, a smelly and irritating gas that would burn your respiratory system and could lead to suffocation; phosgene gas, which was like chlorine gas but caused less coughing and was therefore less detectable and more likely to be inhaled; and mustard gas, the cause of waterng eyes, burning of the throat and lungs and blistering skin. All three are highly undetectable, and caused much fear during the war.
Tunnels
During the First World War, soldiers would dig tunnels to place mines in them. These mines would destroy a portion of the enemy trench, and the soldiers could then take advantage of the confusion to launch an attack. It took a long time to dig a tunnel, and soldiers eventually found out how to discover them. One could stick something in the ground to feel vibrations, discovering a tunnel-in-the-making. Sometimes, a miner would dig into their enemy's tunnels, and the miners would fight down below!
Snipers
Both sides of the Great War would use snipers, highly trained marksmen with telescopic sights on their rifles. They would camouflage themselves, hide themselves in trees, and wait for the enemy in No Man's Land. At the sighting of an enemy soldier, snipers would carefully aim, and shoot the enemy in the head.
Raiding
Raids were often carried out during the First World War in order to capture prisoners and intelligence. Early in the war, Canadian troops would often mount surprise raids, but later vigilance made achieving surprise more difficult. Raids became carefully planned, and would involve the infantry and artillery. The artillery would bombard the enemy, hoping to destroy the barbed wire and kill the enemy's front lines. Then the infantry would move in and attempt their mission.
For More Information
I am by no means an expert on warfare, so if you liked this section, you might want to look into this further. If you would like specifics on Trench Warfare, I encourage you to visit your local library and look for the World War I Trench Warfare illustrated reference guides by Dr. Stephen Bull. It details the armies fighting, the tactics used, and the weaponry with amazing illustrations. It is a bit Anglo-centric, but it is an excellent resource all the same.