While most dog trainers have their own approaches, to each dog and each command there is one general rule that always remains constant for dog training. It is simple, and should never be overlooked. Always choose positive reinforcement over negative punishment for dog training.
First you need to understand why and how dog training works, this will give you a better idea of why positive reinforcement is far more effective than negative punishment. Dog training generally relies on associating. The goal of dog training is to get your dog to displayed a desired behavior, whether on command or simply a positive behavior, by associating the behavior with a desired outcome. This is why using positive reinforcement is much better than negative punishment in dog training.
By using positive reinforcement, traditionally a combination of treats and praise although anything that makes your dog feel as though it is being rewarded will work, you are teaching your dog that displaying a desired behavior results in receiving his desired treat and praise reward. This is how you train a dog to respond to a command, it learns that doing what you want leads to getting what he or she wants. Dogs love treats and your love as well, because of this they respond very quickly to rewards as a form of positive reinforcement in dog training.
Negative punishment as a form of dog training has a couple of different pitfalls which makes it a far worse method to train your dog. First of all it is more difficult for many dogs to associate an undesirable behavior with a negative punishment than it is to associate a desired behavior with a positive reward. This is largely due to pack mentality, and you may not even know that your dog does not understand. You see, your dog will feel submissive to you and as a result will cower and attempt to appease you every time it is punished. To you this looks like it understands what it has done is wrong and it feels guilty, it is however not the case. Whether or not your dog knows what it has done is wrong it will attempt to appease you when you are angry or punishing him or her. This makes negative punishment, by far, less effective than positive reinforcement for training your dog. The next largest reason that positive reinforcement is such a better dog training method is that it avoids some possible adverse outcomes, or side effects if you will. Overly using negative punishments, or becoming angry with your dog, can lead to permanent and sometimes severe behavioral disorders. Very commonly you can instill a lot of fear in your dog, fear can be very dangerous. It can cause your dog to attack other dogs or even small children if it feels threatened. This is a lose-lose situation for both the other party and your dog.
Hopefully you can see the benefits of using positive reinforcement, as opposed to negative punishment, as the key tool in your dog training routine.