OK, I am sorry, but I just found this online and thought that it was a pretty cool way to remember the four MAIN causes of WWI.
M= Militarism, A= Alliances, I= Imperialism, N=Nationalism.
If I have to be honest, out of all the four causes, I think that Militarism was the greatest impact in starting the war. The reason I think that it is, is because it was literally a race in arms. Countries were trying to one up each other on weaponry and try to get better stronger weapons to win the war.