One determining factor for effective positive reinforcement training is the satisfying reward used. Some cats are not "food oriented." The term "food motivated" isn't appropriate when training because most animals, if hungry, can be food motivated. Food oriented relates to the fact that the training subject readily accepts food as a reward. Some pets are not food oriented. Therefore, a different reinforcement needs to be considered. Many animals enjoy play and can be rewarded with a short, fun game. Whichever reward is used, it should be used in small amounts to keep interest in training active. Food sources that many cats like are baby food, freeze dried chicken liver, Temptations (break in half), party mix treats, tuna, deli meat (chicken, turkey), etc.. As for play, some cats like to play fetch or interact with fishing pole type toys.
The clicker, or the word "yes", "good", etc., are all tools called "markers." Used correctly, they "mark" the behavior for which you are training. This tool must be utilized immediately once the behavior has been performed so the pet will realize, "yes, this is what my trainer wants!"
To get started, the marker needs to be "charged." This involves employing the marker, followed by giving the reward/reinforcer. For example, click the clicker or say the word, "yes" or "good" and immediately follow it with the cat's choice of reward (reinforcement), be it food or play. Doing this several times will help the pet realize that each time the marker is used, rewards ensue. When it's perceived the pet understands, training sessions can begin.
One of the best clickers on the market is the "i-click" (products page). It is nice and quiet; therefore, doesn't startle or irritate pets. The click of a writing pen can also work, or even the "cluck" of a tongue. Use what is comfortable and be consistent. Some people even use low tone whistles.
For cats, keep the duration of the training sessions short. Having sessions two to three times a day, but no more than 5- 10 minutes is best. Keep it fun. Whatever behavior is being trained should be broken down to easy, baby steps. Once kitty has the first step, add on the second step and so on. This keeps everyone from getting frustrated when asking too much at one time. If trying to add on the second step, but confusion and frustration sets in, go back to what the pet knows. Keep it fun and end on a positive note. Try again later.