Cats are wondrous, wonderful creatures, and are filled with curiosity. They can be snuggly, affectionate and friendly creatures; often content to nap on a human lap and be stroked until their fur glistens. Some are more standoffish and will only allow the occasional solemn head pat before regally stalking off to stretch and preen in the sunshine. And others are just way out there wild cats, hell bent on running straight up the walls in pursuit of invisible prey, knocking down all who dare get in their pathway. While you cannot change the basic nature of the cat that you have in your home, you can change some of his more obnoxious behavior.
Your first cat-training tip should be to understand why they do some of the things that they do. Some cat behavior is out of boredom, some out of transitional changes as they grow out of kitten stages into adulthood, and some can be a symptom of impending or ongoing illnesses. Knowing which is which can help you to avoid potentially dangerous problems before they become life threatening.
Once you have a basic understanding of the why of cat behavior, you can start working on the things that he will need to change. Make sure that you have a list of the poor behavior, and start with the worst offender first. Try to teach new behaviors one at a time, because too many changes will make the cat confused and potentially worst behaved than before. If a cat is doing something that is possibly dangerous that problem should be addressed first, otherwise, it is at your own discretion.
Remember that training a cat is a matter of patience triumphing over frustration. Shouting at a cat does not work at all, and in fact will bring up a whole new set of issues. Timid cats will become even more fearful, and aggressive cats may take your shouting as an actual threat, so remember that a startled cat will not always react with James Bond coolness- sometimes they bite.
Do not bother with reprimanding your cat, as it is often an ineffective maneuver as well. Cats will learn that getting caught doing the targeted behavior brings about some horrible reactions, so they will simply learn to hide better. This is seen frequently with toileting issues. A cat will stop using his litter box for a variety of reasons, including illness, so that you must find out why. Finding kitty messes after the fact is a pain, but it will not do you any good to drag the offending furball over to the spot, show it to him and then take him to the litter box. Unless he is a brand new cat or you have moved homes recently, he knows full well where that litter box was, he just did not use it. Find out why and the behavior should be stopped. Eliminate all causes, including sickness, and then work from there. Some cats will never use a litter box, but will allow themselves to be trained to use an alternative. Bizet, the big fluffy cat is too big for the litter box, but he does scratch at the door when he needs to go. He is a psycho the majority of the time, but for this one, he deserves a good kitty!