What steps do I need to take to deconstruct the lighting of a portrait?

In general, what steps should I take to deconstruct the lighting on a portrait that somebody else took?

• Are there certain things I should look for that provide visual clues?


• What can I look for to indicate the direction and number of light sources?


• What should I look for to determine the shape of the light modifiers used (if present)?


• What indications of softness and hardness are there?


• Are there methods to judge how far the lights are away?


• Are there any methods to judge apparent light size based on fall off or such?