The NYU Paris staff are very helpful with this, they will help you locate the closest Paris Métro stops are, where you can purchase a Metro Pass. Make sure you ALWAYS carry your Metro Pass with you and have fun!
You get some great student discounts as a European university student, so bring it with you when you travel!
Check out restaurants, and try to find your local grocery store (m). Paris is known for their food culture, visit open markets for fresh produce, meat, and fish. Locate the nearest trams and subway stops!
Stock up on the basics, like toiletries you didn't bring with you from the US.
This seems obvious, but for some reason people forget. Just do it.
as of March 2018
$1.23 = 1 Euro €