Answer all questions to the best of your knowledge. Do not resist the search. Officers do this for their own safety. If the police vehicle is unmarked and you cannot identify the driver as a uniformed police officer, drive below the speed limit to a well-lit, populated spot and then pull over.
Law abiding citizens always pull over for the police.
Stay in the driver's seat with both hands in sight on the steering wheel. Do not exit your car under any circumstances unless asked to do so. Getting out of your car can be perceived as aggressive behavior and a threat to the officer's safety. Turn on your interior light if stopped at night. Comply with the officer's request to see your driver's license.