What to do in a Law Enforcement Encounter

Be polite. Police officers have a dangerous job, so do nothing to aggravate them, even if you feel they are contacting you unjustly. No good can come of being confrontational with a police officer, and if the confrontation escalates you may end up with further charges.
Assert your rights. You have a number of constitutional rights in any given law enforcement encounter. However, many people unknowingly waive those rights. In order to make sure your rights are protected, politely (see rule #1) inform the officer that you choose to remain silent, and that you are requesting the presence of an attorney before you answer any questions or giving any consent to search. Note that this should be phrased as a statement (I would like an attorney before speaking to you or letting you search my things.) and not a question (Do I need to talk to an attorney?). A Deputy Public Defender is available by phone 24 hours a day seven days a week to help you. Law enforcement can call us on your behalf and we can answer your questions.

Again, remember rule #1. Be calm, but assert your right to remain silent and your right to counsel.
Do not lie. Attempting to lie your way out of a situation is not helpful. You will not know how much the officer knows, and telling the officer a lie is simply a way to add more charges to your list. Since you should already be following rule #2, you shouldn’t be answering any questions at all, which will mean you won’t be put in a position where you have to lie.
Cooperate. When given a direct order by law enforcement, comply immediately. It is not your job to determine what is and is not illegal police conduct. Once you assert your rights, it is the officer’s job to follow the law. If he/she does not, it will be your defense attorney’s job to seek a remedy, and the prosecutor’s job to defend the officer’s actions. Do not confront law enforcement over what they can and cannot do; it will not be helpful to your situation.

Any question a law enforcement officer asks you (You don’t mind if I look in your backpack, do you?) should be met with a calm assertion of rights (Officer, I assert my right to remain silent, my right to counsel, and my right against searches. I will comply with any order you give me, but I do not consent to any infringement on my rights). However, any order a law enforcement officer gives you (Give me your backpack) should be met with immediate compliance. Let us lawyers deal with the consequences.