My brother-in-law has been in law enforcement for nearly twenty years. He says that if you get pulled over, you stay in the car, roll your window down, and keep your hands where the officer can see them. If you are the driver, put your hands on the steering wheel. Do not start reaching for your license and registration until the officer asks for them.

I've been pulled before and in addition to the recommendations I was give, I also explain to the officer what I am reaching into the glove compartment for. I also explain why I am reaching into my pocket (that is where I carry my license.)

This is done to keep the officer at ease so that he knows that I am not a threat and so there is no mistaking my intentions.