Teaching your dog to smile is similar to teaching him to engage in any behaviors. You need to use a combination of patience, attention, and positive reinforcement. With enough dedication, your dog can learn to smile on cue
Pay attention to time. Teaching a dog to smile is similar to teaching him any habit, so you'll need to know the basic tenets of dog training. Timing makes a huge difference when it comes to successfully training a dog. • A dog must be rewarded the instant he obeys a command. Many people reward their dogs with a small treat or positive verbal praise, such as "Yes!" or "Good job!"  • Some people invest in a clicker, a small mechanical device that makes a clicking noise when a button is pushed. You can teach your dog to associate the clicker with positive feedback by clicking it shortly before rewarding your dog with treats or attention.
2 Differentiate between rewards and bribes. While treats as a reward can be great motivation for a dog, they begin to come off as bribes when used too often. This can result in the dog only engaging in behavior when he knows there's the possibility of food. • Tell your dog to "smile." Wait 2 or 3 seconds for her to obey this command and only give her the treat if she does. Do not show her you have food until she's already done the trick.  • High energy dogs, particularly young dogs, may not want to engage in training sessions with you. If you're using treats as a way to lure them into the living room when practice time rolls around, stop. This teaches your dog she only has to behave well if food is involved.
Use alternative rewards. Treats are many dog owners go-to, as they're a quick and easy way to reward a dog for positive behavior. You should mix up food-based rewards with other forms of positive feedback. • If you have a playful dog, allow him access to a favorite toy for a few minutes shortly after smiling.  • Rewards like walks or car rides can be given out after a long training session.  • Dogs are natural people pleasers and want to make their owners happy. You can also reward your dog with pets and praise from you. 
Use good posture and body cues. Dogs pick up on body language easily. While training, make sure to convey a sense of authority to your dog. • Always stand when giving a dog a command. If you're sitting your dog will learn to only respect you in that position.  • Keep your hands out of your pockets. The dog might assume you have treats for him there and will learn he only needs to follow orders if food is a possibility. This can also distract him from the task. Keep your hands in view at all times.  • Never hold a bag of treats or a toy or any other objects used as a reward while training. Your dog needs to learn to behave regardless of potential rewards.  • Move from room to room during training. Dogs might assume they only have to engage in the behavior in one area of the house. Ideally, your dog should perform whenever you ask and not just in the living room or bedroom.