We use between with two or more clearly separate people or things.
Example
She choose between Jake and Jesse.
It’s a big difference between a bridges on the river.
What is the main difference between a motorcycle and a bicycle?
Among is used when we want to make reference to a group of people, who have something incoment and we don’t want to separate them.
Example
It is always nice to be among friends.
The rabbit is hidden among the tall grass.
If we are using word difference, then after it’s alway going between, never among.
