Pick your video-recording equipment. An HD camera that can use an external microphone is perfect, such as the Canon 5D. Also get a tripod, extension power cord and extra batteries.
Put a lavalier microphone on the preacher because his words are the most important things to pick up. Rely on an external microphone on your camera as well. Do not patch into the church's audio system unless you have ample time and a large budget.
Decide whether you have the budget for multiple cameras. Take shots from several different angles during the church service if you have multiple cameras. Use two or three cameras if possible.
Focus in on the preacher often because he is the main focus of the video. If you only have one camera, make the majority of the shots of the preacher because you cannot walk around with a rolling camera.
Check your camera's light sensitivity reading. Sometimes the bright light in the church can cause sun streaks. Double check that the automatic light sensor located on the camera is on.