Teach your dog a new behavior by showing the treat and using it to lure the dog into the correct position as you give a command. This is "shaping a behavior." For example, teach the sit command by having your dog stand facing you with the treat visible in your hand.
Step 2:
Move your hand back over the dog's head to lure it while commanding, "Sit." As the dog raises its head to follow the lure, its hindquarters naturally drop to the ground. As soon as this happens, give the dog the treat and generous praise.
Step 3:
Continue shaping the new behavior with the lure until the dog associates the command with the behavior. Once you're sure the dog has the idea, use the hand motion without a treat while giving the command.
Step 4:
Hold the treat behind your back in your other hand while giving the command. As soon as the dog obeys, immediately give praise and the treat as a reward. If you delay, by the time you deliver the treat, the dog may already be doing something else and you'll end up rewarding a different behavior.
Step 5:
Reduce the frequency of the treats as you practice the command with your dog. The dog shouldn't get into the habit of expecting a treat every time he obeys a command he already knows. Give generous praise every time, but don't encourage your dog to work only for the treat.
Step 6:
Reward your dog occasionally with a treat when she obeys one of your commands she already knows well. Use the treat only as reinforcement and an unexpected bonus reward for pleasing you, and remember to give it immediately after the dog obeys. Dogs naturally want to please their owners, and your smile, pat or verbal praise is what it should be working for.
Tips & Warnings
Avoid bribing your dog with treats. Never hold the treat out as a promise to get your dog to obey commands it already knows. This gets the dog thinking it only has to obey you if you cough up a treat, and you're the one being trained to do what the dog wants you to do.