Here's some guidelines for interacting with the cops.

Think carefully about your words, movement, body language, and emotions.
Don't get into an argument with the police.
Remember, anything you say or do can be used against you.
Keep your hands where the police can see them.
Don't run. Don't touch any police officer.
Don't resist even if you believe you are innocent.
Don't complain on the scene or tell the police they're wrong or that you're going to file a complaint.
Do not make any statements regarding the incident.
Ask for a lawyer immediately upon your arrest.
Remember officers' badge & patrol car numbers.
Write down everything you remember ASAP.
Try to find witnesses and their names and phone numbers.
If you are injured, take photographs of the injuries as soon as possible, but make sure you seek medical attention first.