In addition to Wilt's suggestion, take time to look at the lighting on actors in television shows.
Sometimes there is a hard edge on the shadow even though the shadow is filled almost to the point where its not visible.
Other times there is a wide gradual transition from highlight to deep shadow.
In the first, the lighting director selected smallish light sources and low ratio.
In the second they chose a large light source and a higher ratio.
Quantity is only one element when describing the character of light.
The only way to learn how to control the character of light is to understand what elements are involved and how to control them independently and collectively.
Reading books, or web posts, and watching videos is useful, but the real learning results from practicing.
Just take something three dimensional, a light, and start playing. 
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