To teach a dog leave it and drop it, start by introducing the commands separately. Have treats ready and begin by saying “leave it” when your dog is about to grab something he shouldn't be touching. As soon as he stops, reward him with a treat for listening. Once the command has been established, you can work on teaching him to drop whatever is in his mouth after you say drop it. Start by placing an object in front of your pup that you know they will want to pick up (like their favorite toy). Say “drop it as soon as they reach for the item and then immediately give them a treat afterwards. Repeat this until your pup understands what you are asking them to do every time they hear those two words.