One of the main causes of the war was the system of alliances between countries at that time. Alliances such as the Triple Alliance between Germany, Austria-Hungary and the Ottoman Empire, and the Triple Entente between Great Britain, Russia and France, effectively divided Europe into two opposing camps and pitted major powers against each other.
In doing so, major alliances such as the ones quoted above reduced much of the flexibility of the old balance of power in Europe, and that which had existed under the Bismarckian system of old.
These alliances also meant that what might previously have been minor conflicts now had the very real possibility of escalating into full-scale conflicts that would rapidly involve the major powers in Europe, thus dragging the whole of Europe into war.
"The alliances created an excessively rigid diplomatic framework, within which relatively small detonators could produce huge explosions" (A.J.P. Taylor)
This made it much harder for statesmen to preserve peace.
An example of this is the Moroccan Crises that started when Kaiser Wilhelm II visited the port of Tangier in 1905 and publicly declared support for Moroccan independence. The Kaiser did this to test the strength of the Anglo-French entente. This was solved by the Algeciras Conference in 1906 (which ruled in France 's favour). A second crisis broke out thereafter, that also ended in France 's favour, but very nearly resulted in war between France, Britain and Germany (and possibly the rest of