Don’t speak first
It can be tempting to ask a cop “what’s the problem officer?” as soon as you roll down your window, but try to keep your mouth shut until the police officer speaks to you first. An officer will be reading into everything you say, and he is in no way obliged to tell you why he pulled you over until you comply with his rules, so stay quiet until you are spoken to, and then respond appropriately.
On the note of speaking, when you do open your mouth, make sure you do not curse, which will imply anger and frustration, 2 emotions you don’t really want a cop associating with you and your driving.
Read Related: Why is My Child Afraid of the Police?