The goal of teaching your dog to “leave it” is to protect him or your valuables. There are many things that don’t belong in your dog’s mouth. Whether it’s harmful or not, you probably don’t want your dog to eat certain things of yours, and this command can also hinder the investigation of something that he doesn’t belong in.
If your dog has already picked up something in its mouth, use the command “drop it” instead, which will also have to be taught. “Leave it” is important information for your dog to know; it lets him know what’s acceptable to chew on, eat, or investigate.
One method of teaching this command is by using the dog’s curiosity to your advantage. Leash your dog and allow him to play with a favorite toy for a few minutes. When she is sufficiently distracted, throw a new item into her field of vision. Most dogs will show interest in the new item and want to check it out.
As your dog approached the item, give the command “leave it!” At the beginning, your dog will probably still go for it, not knowing what the command means. Stop her advances by using the leash to restrain him. Give her a reward for the desired behavior and let her play with her toy again. Repeat using different items at different times. Once your dog stops when you give the command, try without the leash.
Another method uses food. Place a treat in your hand and let your dog know you have it there. Allow your dog to sniff your hand, then close your hand around the treat and say “leave it!” Your dog might lick and nudge your hand, trying to get the treat. See also this article on how to chose the right puppy for you.
Don’t give in, and keep your hand outstretched in front of your dog. Only use the command once. As soon as your dog turns away from your hands, praise him and give him the treat. Repeat until your dog will leave your hand alone when you say “leave it.” When your dog jumps up to people, there are also a few fine tricks that you can read all about here.
This is a valuable trick to teach your dog. It will be easier to watch out for him and discourage him from investigating potentially harmful things. You’ll be happy you can help protect your dog from its natural curiosity. Every command taught takes time and patience. With consistency, you can train your dog lots of useful things to keep him safe and out of trouble.