Some large shops such as grocery stores may accept US dollars or Euros however the exchange rate will not be favorable. It is best to travel with a combination of either US dollars or Euros, a credit card for emergencies and your bank card. Travelers’ cheques can be quite hard to exchange and generally the exchange rate is much less than for cash. The bills/notes that you bring of foreign currency to exchange should be in very good condition without even slight rips or tears and not old nor faded. Peru is particularly picky in regards to this point.
Do dress to blend in with the locals. You may be on vacation, but the thieves are not. The more you blend in, the better. Do not wear that new Brazilian national soccer shirt you just bought. Save it for the post-trip homecoming party, and never wear anything around your neck.
Do make a photocopy of the relevant pages of your passport and carry that instead of the original document. Leave the original in the hotel safe.
Do not assume that because Paulistanos are reveling with abandon during Carnival that you should, too. You certainly will be asked to join in the madness, but be aware that plenty of pickpockets and thieves are also doing the same thing.
Do try the local food and beverages. Brazil is a great place to eat and drink. But if you want local ambience, don’t go to dinner too early. Brazilians don’t eat dinner until around 9 pm.
Don’t arrive on time for dates or informal social gatherings. If you arrive at a house party at the appointed hour, the hosts will still be in the shower or putting on makeup.
Don’t take your sartorial clues from the natives. Paulistanos may dress very casually and without seeming concern for modesty, but following suit will only subject you to unwanted scrutiny.
Do take a gift if you are invited to an Argentine’s home for dinner, and do dress nicely—shorts are never appropriate (unless you are a college student). In clothes-conscious Buenos Aires, they’re not a good idea on the street, either. Sandals are definitely out.
Do remember that grand churches are more than museums. Although women no longer have to cover their heads or even shoulders, it’s still polite to be conservative in dress.
Don’t talk about international political matters. It’s not a good topic in the best of circumstances, and many Argentines still resent the U.S. government’s lukewarm support for their country after the 2001 economic collapse.
Do pamper yourself in a peluqueria (beauty salon). Their services are cheap and fabulous.
Don’t order wine from any other country when in Argentina (unless in a fine French restaurant). Argentine wine may not be the world’s finest, but you will be told—unceasingly—that it is.
Do feel free to sit and people-watch in cafes after you’ve finished your coffee. This is a time-honored custom in Buenos Aires, and servers expect it.