If the police stop you, stay calm. Don’t run. Don’t argue. Ask if you are free to leave. You have the right to remain silent and you do not have to consent to search of your belongings.
If you are arrested, do not resist arrest – even if you think the arrest is unfair. Tell the officer that you want to remain silent and ask to see a lawyer immediately. You can make a local phone call – but don’t talk about the details of your arrest while on the phone. If you think arrest is possible, make emergency plans in advance with your family and your lawyer.