Motion trails and bouncing balls

I'm using motion trails to smooth out the movement of the feet.

And for getting the ball bouncing with a nice curve.

Squash and stretch

Parenting the ball to the dogs head, then animating the switch on when he catches it, so the ball isn't permanently stuck to his mouth. 

Using grease pencil to get the tail movement down.

And afterwards, putting an expression on the face with the eyebrows.