Any behavioral specialist (and any parent!) will tell you that you get better results with rewards than you get with punishments, and with a little of thought, it's easy to see why this is the best way to train your dog. For your dog's own safety and for your own sanity, you'll find that using a rewards-based system is one of the most effective ways to train your dog and to make the training stick.
The first thing that you need to be aware of is that your dog wants your praise. You are the leader of the pack, and your dog definitely wants to please you. This is an evolutionary trait that you can use to your advantage, so make sure that you do!
Positive reinforcement is a great way to train dogs, and you'll find that with just a little bit of work, even older dogs can be trained to follow basic commands. Don't ever believe that an old dog can't learn new tricks, so make sure that you teach any dog you own basic commands like "sit," "lie down," and "heel."
The key when starting out with the positive reinforcement method is to give your dog a cue that you will use consistently throughout training. It doesn't matter whether it's word or a gesture. Your cue will signal your dog to perform the desired action so make sure it's something that's relatively easy to understand.
As an example you may choose to train your dog to sit down. Start out by telling him in a clear, moderate tone, "sit." You follow your command by assisting him in that task by pushing his back legs down. Once the task is completed be sure to lavish your dog with lots of praise. You may even want to give him a little treat. Your dog needs to know you're happy with what he's done.
Remember that should only reward your dog when he performs at your command. If, for instance, he comes up and sits or rolls over without any prompting for you, do not give him a treat. If you do, you can think of it as him training you, instead!
Also keep in mind the fact that if you are trying to train a destructive behavior out of a dog that you should not scream at him. Losing control and yelling or hitting your dog will only teach him to be afraid of you, and nervous dogs will often do a lot more damage than calm ones. Only reprimand your dog if you actually catch him in the bad behavior, so make sure that you are there to see it!
Training a dog does not have to be a chore. It can be a great way to learn more about your dog and to get to know him well and for the two of you to work together. Take advantage of this opportunity to do just that while training your dog to follow basic commands!