Target training involves getting your cat to go to a target consistently. This can be as simple as a tennis ball on a stick or even the end of a pencil. You want to consistently use the same object for your target. Once you have a target, you want to start encouraging your cat to touch it, either with a paw or his nose -- your choice.
First, hold out your target item. When your cat begins to show interest by sniffing at the target or making contact with it, give him a treat. Once you've established the connection between the target item and a treat reward, start moving the target away from cat. Any time he follows the target and touches it, reinforce the connection with a reward. Once the cat consistently goes to the target, you can attach a verbal cue, such as "come" or "here" to the activity.
Target training can form the basis for more complicated tricks down the road, such as twirling or even walking into a carrier on command.