What were the strengths and weaknesses in military formations of the Great Powers in World War I?

The Central Powers, comprised of Germany, Austria-Hungary, and the Ottoman Empire, had fewer soldiers than the opposing force in World War I. During peacetime, their combined military forces totaled 1,242,000, while the Entente, made up of France, England, and Russia, had a peacetime force of 2,170,000. During the war, the German army totaled 2.15 million, and the Austrians totaled 1.3 million. The forces of the Central Powers were dwarfed by the forces of the Serbians, Russians, French, and Belgians, which totaled 5.6 million.
Despite the superiority of the Entente's forces, Germany and its allies were able to fight on two fronts and hold off an Entente victory for four years. Their military formations were superior to those of the Russians, as the Germans boasted better leadership by officers and better trained rank and file soldiers. However, the Entente had superior technical advantages, as the Germans struggled to use new technologies to their advantage and to transport their forces from the Eastern to the Western Front quickly once Russia dropped out of the war. Instead, Germany tended to rely on the bravery of its soldiers in battle. They required more technical expertise with weaponry—which they were to develop after World War I.
After the Battle of the Marne, the Germans settled into a stalemate. The Germans tried to end the stalemate, in which the opposing forces settled into trenches on the Western Front, with counterattacks and infiltration techniques that involved infantry companies accompanied by trench mortar companies and flamethrowers. The Entente forces did not initially understand these new tactics and kept trying to break out of trench warfare to resume a traditional battle approach with a mass of infantry.
While the German troops may have been better trained and tactically superior, they could not defeat the Entente forces, which had superior resources and manpower. Though the Americans struggled to arm and equip themselves once they arrived in Europe, they and the other Entente powers eventually wore the Germans down. By the end of the war, the Germans could not muster sufficient manpower to defeat the Entente.