Promos are very important in film making. You need lot of practice in video editing to make meaningful promos.
Like you write a summary of an article or a paragraph similarly you have to make a summary of the event. Ask yourself why you want to make it? Is it to increase sale or convey a social message or is it for publicity? What you want the viewer to feel after watching this video? Keep the duration 1 to 3 minutes. Decide about the style. Wheather it would be animation or interview based or narrative style. Have a beginning - middle - and end. As a cinematographer also keep the promo shots in mind.
