Look for safe, well-lit areas, if at night. Pull off or into a place where you can communicate with an officer. Put your vehicle into Park.
Pull your camera out and get it turned on and ready to tape. When the officer steps up to the window, be calm and polite. Also, point your camera at him from a safe distance from him while the interaction happens from start to finish. The Landscape view is a better view than a portrait view as it shows a larger area your filming.