When I was in high school, I was taught that a preposition is "anywhere a cat can go." I had a pretty creative English teacher. Basically prepositions are those little words that indicate a place. Using my English teacher's creative idea, I created a story about a stuffed cat (the family pet met an untimely end) that has to be placed somewhere in the home. Hopefully the story helps the vocabulary stick.
Here is a simple table with the prepositions in the story (plus a few more that didn't fit).
à côté de
in front of
of / from