There are two methods to teach this trick. The first method involves your dog targeting your hand with his paw, and the second encourages your dog to move away from pressure.
Method 1: Wait him out!
1. Hold out your empty hand, palm up, at a height close to your dog’s knee level.
3. Your dog will probably sniff your hand, lick your hand, and eventually he will try some other tactics, such as pawing at your hand.
4. The moment your dog lifts his paw (even if he hasn't made contact with your hand), tell him "good dog!" and reward him with a yummy treat.
5. Repeat this waiting game until the dog is lifting his paw into your hand. Keep rewarding him and start adding a verbal cue. Say "shake" as you present your hand and soon your dog will be eagerly shaking paws with you!