Proper dog training technique begins when your dog is a puppy (but if your dog is old, you can definitely still teach it new tricks). Many people say that training puppies isn't possible which is simply not true. No matter what age your dog is, you should begin training right now.
The first thing you should do before you start training, is find a good dog obedience school which will help you learn the basics. After attending the beginners classes, you can and should most of the training at your house. When choosing a place for training, you should choose one that is as quiet and calm as possible. Noise and other distractions can greatly hamper any good training techniques. Once you've mastered a few commands in this type of environment, you should take your dog to other areas that may be more distracting. While this can be frustrating at times, it will be rewarding in the end because you can get your dog to listen to your commands regardless of the distractions around him. Using this type of dog training technique will help you get to point where your dog will heel masterfully while walking him through the park.
Choosing the proper rewards is imperative to excellent dog training. Failure to reward your dog properly when he learns or masters a trick can retard the training process greatly. The more you reward him when he does things right on the other hand, will cause him to learn faster and respond quicker to your commands. For choosing a reward, choose a special treat that your dog loves but only gets to have when he performs correctly.
Also on the idea of rewards, make sure you praise your dog when he is doing things right! Dogs love praise and gratification and will respond positively to it. Oftentimes we notice when they do something wrong like being too noisy, but never notice when they're being quiet and calm. Praising your dog for the little things will not go unnoticed in your dog's behavior.
Punishments for your dog on the other hand should be done seldom and should lead to praising when they do the right thing. Repeated "NOs!" can end up going being ignored by your dog if you do it too much. If your dog is chewing on your favorite shoes, instead of just saying "NO!" and taking away the shoes, good dog training technique would be showing your dog its toys and encourage him to chew on them instead after removing the shoes. After your dog does what you want him to do, reward him and praise him for good behavior. You will see, over time, that your dog will do much less bad things and many more good things.
Here are some articles about dog training you may be interested in:
-Dog Training School