Teaching a cat to use the litter box is very different from house training a dog. “Cats are naturally inclined to eliminate waste by pawing through a sand-like substance in a private location.” Most problems people experience when litter training a cat are caused by human-error.
Here are some reasons why your cat might be avoiding its litter box:
Wherever you choose to put the litter box (or multiple boxes), be sure it can be reached easily and quickly. You may want the box out of sight (and smell); however, your cat needs to be able to access it. The best place for a litter box is a “clean, quiet, and low-traffic area where the cat feels it has privacy.”