Trainer Meredith Gage of Pawsitive Experience teaches you and your dog the leave it command.
The “Leave It” Command
This command instructs your dog to leave it alone -- do not touch.  It is a safety cue to prevent them from picking up things we don’t want them to touch, including things that could make them sick.  It also comes in handy when you drop that steak that’s ready to go on the grill!
Here’s a step-by-step on how to train it.
Step One. Start with two treats.  One is low value, like a dry biscuit or piece of kibble, and the other treat is high value, like a piece of chicken or cheese.  Place the low value treat in one hand and cover it, making a fist.  The hand with the high value treat is hidden behind your back.  Offer the fisted hand to your dog so they can smell it and then say the word “leave it” ONLY ONCE (more than that and the word will be a distraction to them).  Your dog will continue to sniff and investigate the hand with the low value treat, and the second they give up and back or look away, say your reward marker word (“yes” or “good”), and bring the high value treat from behind your back and give it to him.  Repeat this about 20 times until you get a success rate of 90%, i.e, your dog immediately backs or looks away from the treat when you say “leave it”
Step Two. Now place your fisted hand down to the floor.  Repeat the steps that you did above.  Do not move to the next step until you have a success rate of 90%.
Step Three. Now for the hard part.  Up to this point your dog has learned to leave things that he can smell but not see.  Place a low value treat in your hand and as you a taking it to the ground, say the word “leave it.”  Place the treat on the ground in plain sight.  If your dog doesn’t move towards the treat, even for just a split second, use your reward marker and then reward.  It he does go towards the food, block him with your hand, or cover the treat so he can’t have it.  Slowly build duration by withholding the reward longer while he looks at the goody on the floor.  You will have more immediate success at this step if you spend extra time on steps one and two.
Step Four. Drop a goody on the floor and just when you release the goody, say “leave it.”  Reward when he does not go for the goody.  Step on the treat or body block him if he does.  Build duration by withholding the treat longer
Step Five. Put a plate down with goodies.  Put your dog on a leash and place him 4 or 5 feet from the goody plate.  Start walking towards the plate, and when he gets close to it say “leave it” and when he stops or turns around to you, reward.  If he goes for it, say uh-uh and pull back on the leash.
Step Six. It’s now time to take this out on the road and when your dog shows interest in something, say “leave it” and reward when he backs away.  When my dogs are off leash, I say “leave it” and then “come” so I move them away from the temptation and back to me where it is safe and I can leash them.
Remember to take each step slowly and go back a step if they aren’t getting it at the next level.
Meredith Gage
Pawsitive Experience