Staying out of trouble in Rio de Janeiro is very easy indeed. Yet, most tourists I know of had a bad experience caused by some basic mistake they would never make in their home countries.

Follow the guidelines below, use your judgement and you should be mostly safe.

And last but not least, always remember: Brazilians speak Portuguese, not Spanish. Most people do not speak English, or can only speak/write very basic English. Spanish knowledge may help you, since most people will be able to understand a substantial amount of what you're saying.