Traveling to Sao Paulo, Brazil?

Hello, I am 18 years old and traveling to Sao Paulo, Brazil in a few days. I will be staying for 2 weeks with a family of an exchange student who stayed where I live. I was just wondering of any tips on things I should pack, or what to expect about food or tradition that I should know. I am pretty much clueless so any information would be helpful. Thank you!