Some cats demand a degree of privacy and will not use a litter tray in an area with a lot of human traffic. (best-cat-art.com)
Once they reliably use the litter tray in their cage trial giving them more free range time outside, if they go to toilet put them in their cage. (vetbabble.com)
As a newborn kitten I need to become familiar with using my litter tray as early as possible to help prevent those little accidents occurring in the corner or behind the TV. (consciouscat.net)