The "leave it" command is used to prevent your dog from picking things up. It allows you to tell your dog not to touch the things that you don't want him to have, like a child's toy or a dirty tissue or any one of the hundreds of things he may try to pick up and chew. This command can also keep your dog from eating something that might be harmful to him.
"Leave it" is fairly easy to teach. Here's how to do it:
What You Need
Keep Training Sessions Short
Training sessions should be kept short and upbeat. About 5 minutes for each training session is enough. If your training sessions go on too long, your dog may become frustrated and start making mistakes.
Show Your Dog a Treat and Give the Command
To start, take one of the treats in your hand, and allow your dog to see it. As soon as he is interested in the treat, give him the command "leave it," and close your hand so that he cannot get the treat.
At first, most dogs will stick their nose in your hand and possibly nibble on your fingers or paw at your hand in an attempt to get to the treat. As soon as your dog stops trying and pulls away a little, praise him (or click your clicker) and give him a treat. The treat you give him should be a different one then the one you told him to leave.
It's very important that you keep the treat covered at all times when you are in the beginning stages of training this command. If you accidentally allow your dog to get a treat before you give the click or praise, he will try even harder to get the treat next time. One or two mistakes will not make much of a difference, but if your dog is getting the treat a few times each training session, it is going to take him much longer to understand what "leave it" means.
Increase the Time and Distance
Once your dog is consistently backing away from your hand, you can make things more difficult by increasing the time you make him wait for the treat. In the beginning, you should give the dog a treat the second he pulls back from your hand. You can slowly add a few seconds until you are able to go several minutes while your dog waits patiently for his treat.
Next, you can begin to move the treat. Put it on the floor a foot or two away from your dog, but keep your hand close enough to cover it should your dog try to take it. Once your dog is consistently leaving the treat there, you can move it a little closer to him.
After several training sessions, you can begin to step away from the treat yourself. A good way to begin this is to drop a treat on the floor while you're standing, and give the "leave it" command. Have a foot ready to cover the treat in case your dog makes a lunge towards it. Slowly increase your distance from the treat over several training sessions. Soon you'll be able to tell your dog to leave a treat on the floor when you are standing on the other side of the room.
Practice with Other Items
Once your dog has mastered "leave it" with treats, you can start practicing with other items. Put one of his toys near him and tell him to leave it. As soon as he backs off the slightest bit, give him praise and his treat. Keep practicing with other items. Before long your dog will learn to leave any item where it is when he hears the "leave it" command.