Cats are known for being stubborn and having their own ideas about how to do things, and actually this is a part of their charm - it makes them fun and interesting to live with. However, a bit of obedience is always welcome, and it is not impossible to train your cat, at least in some ways. But first of all, you must realize that a cat should be loved for being a cat. You should not try to teach her unnatural things, such as to sit or stay (you can always get a dog if this is what you want) or, much worse, to use the toilet. These are not reachable goals and you should definitely not stress your animal with them. But teaching the cat to use the litter box instead of your shoes, to use the scratching post instead of scratching your couch and to eat healthy food that may not be so tasty for her as a snack are all very possible goals, although accomplishing them may require some time and patience.
Many people whine about being treated as slaves by their own cats. There are even funny quotes about cats' behavior. One which is attributed to Terry Pratchett says that in ancient times, cats were worshipped as gods; they have not forgotten this.
But the truth is cats can be so lovely that the humans naturally try to please them. If the cat wakes you at 5 in the morning, meowing for food, you get up, feed her and pet her – therefore, you unintentionally reward her for obnoxious behavior.
When trying to train your cat, keep in mind that protocol is important. Cats do not understand English, reason that may work for humans do not work for them and they only learn by experience. A pleasant and rewarding experience will, naturally, be repeated. An unpleasant experience will be avoided. The idea is simple: always reward your cat for things that you want her to do, and whatever you do not want your cat to indulge in must never be rewarding or fun.
Reprimands and punishment do not work with a cat instead, you should focus on making your relationship fun and rewarding. Cats generally overreact when they are bored and seek your attention. They scratch the furniture because they have the natural desire to scratch and climb. You can provide her with a variety of scratching posts that can be found in any pet shop.
You may also need to teach your cat to use the scratching post instead of your furniture and the easiest ways to do this is to put her favorite food treats on the platforms, attach toys so they dangle down or rub the post down with catnip. Be sure to praise your cat as soon as she makes the first scratching moves on a scratching post. She will learn to love it. If you find your cat scratching the furniture again, make something that you know she dislikes (but NEVER something violent!): you can spray some water in her direction, whistle or put some fresh orange peels around.
The key to having a great and fun relationship with your furry slave master is to understand your cat's behavior.