What is a good storyboard?

A storyboard is one of those aspects of filmmaking which help you "see" the movie before you have created it. Storyboarding also helps the animator determine whether the shots are dynamic or not. The storyboarding process form widely known today was developed at Walt Disney Productions during the early 1930s in order to help directors visualize the scenes and find potential problems before they occur.
DreamWorks advises film directors and cinematographers to avoid flat staging in their storyboards because the image contains three vanishing points. Thinking in 3-point perspective makes the storyboard appear more dynamic, adds more depth and volume. Drawing a grid also puts the character on an easily discernible plain which helps you gain more control over your character.
In order to add depth, texture and sense of location the use of foreground, mid-ground, background and far background is very helpful.
When dealing with multiple characters one easy way to organize them is labeling, because without some sort of order to how you stage your characters, cutting back and forth between them could be confusing to you, the editor and the audience.