How did the causes of WWI relate to Wilson's 14 points?
In order to understand this, let us look at the most important aspects of the 14 Points. As we do so, we can lay out how each was related to the beginning of the war.
No secret diplomacy. One thing that helped start the war was the fact that countries made secret alliances with one another. This made it hard for countries to really know how dangerous a war would be. Wilson wanted Country A and Country B to openly announce their alliances so that a Country C that wanted to fight Country A might be deterred by knowledge of the alliance.
Free trade. If all countries could trade with all other countries freely, empires would be less important. Countries would not have to fight over empires as a way to have sources of raw materials or markets in which to sell.
Freedom of the seas. The US had been pulled into WWI due in large part to the German submarine blockade of England. If freedom of the seas were guaranteed, this could not happen again.
Self-determination. One major cause of the war was anger on the part of some ethnic groups (like Slavs) because they were ruled by other ethnic groups (like Germans). Self-determination would prevent this sort of resentment.
Collective security. If all countries guaranteed that they would fight any aggressor, no country would invade another as happened at the start of WWI.