Militarism lead to WWI because it showed that the countries involved in WW1 had great military power, and so they weren't really scared to go to war.
P.S if you really want a way to remember the main causes of WW1 they are
M- Militarism
A- Alliances
I- Imperialism
N- Nationalism
{EXTRA} Nationalism is to have a strain pride in one's country.
Imperialism is the belief of expanding your country's power and influence.