Shorter is better. We advise a video to be in the 1- to 3-minute range. If you don’t think your story can be told in that range of time, consider a short series or reconsider using video.
Show, don’t tell, or be visual with a narrative. Film is a visual medium, so your message needs to translate visually. Ask yourself, why should my audience watch this story instead of reading it? What is it about this project that can only be communicated through video?