The following qualities for explanatory data visualizations were described in the free, online course Data Visualization and D3.js.

• understand the context- who will be viewing the visualization, what is the cultural context?
• choose appropriate type of visual- should it be a map, chart, etc?
• identify and eliminate clutter – remove non-essential details, show only informational design elements
• direct audience attention – show the viewer what is important, guide their experience through the visualization
• tell a story – tie your visualization to a larger narrative