Some of the reasons for increasing tensions within world powers prior to ww1 included:
Nationalism
- There was a belief amongst European nationalists that people who shared a common language and culture should become their own country
- Created mistrust and hatred between nations
- Encouragement, particularly in Eastern Europe, where Russia and Austria-Hungary were rivals, to rise up and fight one another - the Russian encouraging the Serbs and other minority groups to fight the Austria-Hungarian empire
Imperialism
- Countries wishing to expand their empires, such as what happened in Britain, France, Germany, Italy, and Russia between 1870-1914, for imperial empires in Africa, Asia, and the Pacific
Militarism
- European nations expanding their armies to protect and defend themselves from other imperial empires
Alliances
- To protect themselves, nations began forming alliances with other European countries (E.g. Triple Alliance and Triple Entente)
- Agreement of multiple countries to come to one another's aid should a country be attacked
Hopefully this will help.