Have an idea of sites you want to visit and things you want to do during your trip. Do some research on travel blogs and communities. You should ask friends and family who have traveled before about places they enjoyed the most. Read through site-specific guide books like Lonely Planet, Let's Go, Rough Guide, Rick Steves, or Frommers.
Book all travel far in advance. However, do not book anything until after the first week of classes. You may find there are NYU-sponsored trips already in place.
Some helpful sites:
"I went on an 18 day adventure to Austria, Czech Republic, Greece and Italy. My favorites - which I highly recommend - are Salzburg, Vienna and Prague. While every city and country that I visited is culturally unique, Salzburg and Vienna were highly unassuming cities that took me by surprise. They weren't outrageous or completely exotic, but they were both so beautiful in their own breathtaking ways. Prague is a gorgeous city with an array of building, architecture and sites that combines old Prague with its very interesting recent history."
- Olivia, NYU Madrid student