Sometimes you just come up with these out of the blue and other times you really have to work it out to make sure you're leading the viewer's eyes properly.
When you are watching cartoons look for these types of compositions to see if they are used for a purpose. You'll find them mostly in feature films. There's not really enough time in the production schedule on a 1/2 hour show to plan out a very deliberate composition, that's why you won't see too many on Saturday morning.