#1: It is all about the size: The bigger the box the better. Ideal size is big enough for the cat to turn around in the box without touching the sides of the box (1 ½ times the length of your cat from nose to base of the tail). Rubbermaid® containers or “under the bed” sweater boxes make ideal litterboxes.
          

     
#2: Covered vs Uncovered: When given a choice, cats prefer uncovered to covered litterboxes. If you are unsure which your cat prefers? Place a covered box next to an uncovered one and see which one you cat visits more frequently.
       

         
#3 Low Sided vs. High Sided: Some cats prefer a low sided box to a high sided one. If you have a cat eliminating outside the box but right next to the box, try a low sided box. It may be your cat has some arthritis that could be causing pain when entering the box. A low sided box makes it easier for your cat to get in and out of the box. Low sided and disposable boxes are also ideal for kittens. For cats that spray near the box, try a higher sided box.
       

       
#4 What about litter? Clay, non-scented, clumping litter is preferred by most cats over any other type of litter. Do not forget: no liner (cats often don’t like how a liner feels in their claws), scoop the box daily, refresh litter when needed, and completely clean the box at least once a week with mild, non-citrus smelling soap and water.