This article is from the Problem Behaviors in Cats FAQ, posted to rec.pets.cats newsgroup. Maintained by Cindy Tittle Moore with numerous contributions by others.
You cannot discipline cats as you would dogs. Dogs form social hierarchies that you can take advantage of by placing yourself at the top. Cats form social groups only by necessity and the arrangement is based on respecting territory, not by respecting the "top dog". Many mistakes made with cats are due to thinking that they will react like dogs.
Do not ever hit a cat or use any sort of physical punishment. You will only teach your cat to fear you.
* You can train your cat not to perform inappropriate behavior by training your cat to perform other behavior alternative to or incompatible with the inappropriate behavior.
* Since cats hate to be surprised, you can use waterbottles, clapping, hissing, and other sudden noises (such as snapping, "No!") to stop unwanted behavior. However, be aware that these tactics will not work when you are not present. In addition, immediacy is key: even seconds late may render it ineffective. You must do it as soon as the cat starts the behavior.
* The face-push has been described by various readers. This consists of pushing the palm of your hand into the cat's face. This is best used when discouraging something like biting. Don't hit the cat, simply push its face back gently. You might accompany it with a "no!"
* Making certain behaviors impossible is another tactic. Think "childproofing": keep food in containers; keep breakable and/or dangerous objects out of reach; make sure heavy objects, e.g. bookshelves, are stable. Look for childproofing gadgets and hints and think how you can apply them to preventing cat problems. Even when the analogy isn't perfect, physically preventing problems is still a good guide. E.g., defrosting meat? Put it in the (unheated) stove, not out on the counter.
It is always best to train your cat away from undesireable behavior as soon as possible, as young as possible. You will have the most success training your cat when it is young on what is acceptable to scratch and what is not. Never tolerate it when it is "cute" since it will not always remain so.