What most naturally follows?

How to teach your cat to give a handshake
Obtain a clicker.
A clicker is a small plastic box that contains a strip of stiff metal. When pressed, the metal makes a distinctive " click-clack " noise.
Clickers can be obtained in most pet stores. The theory behind clicker training is that the cat will learn to link a sound (click-clack) with a reward (tasty treat).