It’s always a good idea to have an actual script for your video (and even short storyboards in some cases). This seems obvious but you might be surprised how many people just turn on the camera and wing it—often with disastrous results. 

Your strategy, topic, and target audience should determine the length of the video. And the length of the video can often dictate the script. What is shown and heard during the first 15 seconds of your video? The answer is certain to be very different if your video is 15 seconds versus 15 minutes. What emotional “hot buttons” do you want to push within your video viewers? What action (if any) do you want a viewer to take as a result of viewing your video?