Between
One to one relationships.
Among
Indistinct or non-specific relationships.
In the middle of two elements
My nose is between my eyes.
The elements are separate and distinct
For my birthday I had to choose between a computer, a phone, and a tablet.
Elements are not distinct and viewed as a group
I can see some familiar faces among the crowd.
Part of a group of people or things
I have worked as a teacher among other things.