Your story needs a narrative.
The hook is what makes the viewers want to watch, it captures their attention. The hook is the bit of the intro that reveals what will happen.
Another key element of your film is compelling characters. The audience needs to care about your character and they are one of the key hooks in your film. Finding these characters may be a challenge but you can meet them from blogs or face to face. How you present these characters and the first impression the audience receive of them is key to whether or not they will connect with your character. If the audience find something they can emphasize with it will help this connection also. As a filmmaker, it is your job to develop strong bonds with your subjects and make them feel more comfortable so they will be themselves on screen.
Tension is another crucial element, it needs to build up throughout the film and it is one of the key reasons people watch.
Depending on the subject, conflict can make your film very engaging. People want to see opposing views.
The resolution is the pay off so to speak, it is the reward the audience get for watching. It doesn’t have to take the viewer from A-Z but the story definitely has to move from A.