Miranda rights are only required during a custodial interrogation, which means you are in police custody (arrested or not free to leave), and the police are actively questioning or interrogating you. If the police arrest 50 people at a protest, put them in a van, process them at the precinct, and never ask them a single question about their conduct, the police never actually need to read them their rights.

Any self-incriminating statements you make before your rights are read to you generally cannot be used against you in court as primary evidence (this is the Exclusionary Rule). Note that that's as primary evidence, though. If you mention the kilogram of illicit substances hidden in your shoes before they Mirandize you they can't use that statement in court, but they sure can use that kilogram of illicit substances as physical evidence.

So other than the bare minimum of what the law says you have to say, always remember that it's Friday.