Pre-Production

Have a firm idea of the story you are trying to tell.
Do an outline based on your story.
Do your best to understand what pictures will best tell the story you have in mind - visualize your story.
Make a list of names and contact information for the major players in your story.
Know where you are going to shoot. Visit your shooting site BEFORE you actually go there to shoot. Get familiar with the territory. Think about what shots will work and what might be visually interesting.
Get permission to shoot where you are going to shoot.
Get permission to shoot the people you are going to shoot - have them sign a talent release form.
Make a schedule for shooting that accommodates the people you are going to shoot and where you are going to shoot.
Make a list of questions you want to ask the people you are going to shoot. Make sure the questions you want to ask will help the people you are going to shoot tell your story.
Make a list of equipment you will need to shoot your story. When it comes time to go to the shot use this list as a checklist so you don't forget things like batteries and videotape.
Remember that the more carefully you plan the smoother it will go when you actually start shooting and finally editing your story.