Before you can start animating, your cat needs a character design. This will have an enormous impact on how you animate your creation. Decide on some descriptive words like lazy, frisky, evil, manipulative, silly, friendly, grumpy or fickle. You can string together several descriptive words to form a personality.
Draw out the cat based on the personality descriptors. For instance, if the cat is lazy, perhaps the eyes will appear half shut while the cat lies on her side. If the cat is hyper or frisky, her eyes and mouth could be wide open and the body posture could be tall and straight.
One of the easiest ways to animate a character by creating it from several pieces of paper. You can use construction paper if you want to avoid coloring the cat. If you would like to add more detail, card stock will work well. Cut out a separate head, body, legs and tail. You can fashion the ears separately if you wish to animate them moving from down turned to upright.
If you would like to show the cat blinking, winking or falling asleep, you can create a few eyelid pieces, ideally one fully shut and one halfway shut. You can also make separate front paws to add more animation.
You can now lay the pieces of the cat on top of each other and begin animation. Create movements by moving pieces like a leg or the tail slightly and then taking a picture. Move the piece again and take another picture. You can animate several pieces at once to create more complex movement. For instance, you can create a quizzical look by slowly tilting the cat's head to one side while moving the ears from sideways to straight up.
One of the easiest ways to capture each frame of animation is by using a digital camera. You can set the camera up on a tripod and angle the camera down to snap a photo of each frame. It can help to use a remote control for your camera if you have one. You can then import these frames into your computer and sequence tthm with a program like iMovie or Movie Maker to create an animation.