Staying quiet is not enough — you must clearly and explicitly say "I am invoking my right to remain silent" or "I want a lawyer." If you eventually start talking after being read your rights, that conversation can be used against you.
A suspect who has been read Miranda rights and remains silent for hours before voluntarily speaking has not invoked the right to silence. Suspects must unambiguously invoke their rights.
You must actively and clearly invoke your Miranda rights. Say explicitly: "I invoke my right to remain silent" and "I want a lawyer" — then stop talking.
LEGAL DISCLAIMER: Case summaries are for educational purposes only and do not constitute legal advice. Consult a licensed attorney for advice specific to your situation.