An aquaintance of mine (who was/is a cop) once told me the following:

    When you get pulled over, pull into a well-lit, open area. If it is raining, pull over under a bridge or some sort of covering - within reasonable range. Once you are pulled over, turn on the cabin light, roll the window down and place both hands on top of the steering wheel. The cop will invariably come up and ask for your license and registration; you should say something like: "My license is in my wallet, which is in my right back pocket and my registration is in my glove compartment. I will retrieve them in that order." This shows the cop that he is in control of the situation, thereby making him comfortable. If you look the part, he might even assume you know someone well enough to fix tickets and his effort would be wasted.
    When you reach for your ID and registration, be sure to break eye contact. This may not mean much to you, but cops know that killers always maintain eye contact before striking their victims - constant eye contact might make some cops very nervous. Hopefully everything will run through fine, follow the above advice for talking to the cop, roll up your window and drive on.