I'm in an advanced history class, and we have an assignment to analyze what you think are the three largest causes, in an essay, of WWI. By no means am I asking anyone to do the essay for me I'm just asking for some opinions to help push me in the right direction. Especially since there are so many causes to choose from I figured I'd ask professionals. If I'm asking a question that has been asked already I apologize, just direct me to that post so I'm not lost. Thanks!
It's more like making a pizza, all the ingredients are important.
Are you looking for July crisis causes? Certainly the Blank Check, German War Plan, Russian mobilization, Russian support of Serbia, ambiguous British statements about if they would stay neutral, etc.
Going back farther, you can look at the naval arms race between Germany and England, the Balkan Wars, Moroccan Crisis, or all the way to the Franco-Prussian war, Crimean War, etc.
In short, you really need to look at the history and form your own conclusions to do well on this assignment.
I assume this is high school. The answer to this question is a lot like this clip from the Simpsons: http://www.youtube.com/watch?v=y8VCbvMoCV8
The causes area really complex, but what they are looking for you to hit is nationalism, the alliance system, and jingoism. Nationalism from the Serbian and Russian sides, the Alliance system prompting things like the blank cheque, and of course dragging the whole continent into the conflict, and jingoism for the war fever and excitement for conflict leading up to that war, as well as in the first few months of the war. These three points hit more specifically are going to be what an AP teacher is looking for. How you explore and flesh them out is, of course, up to you.