Become a dog whisperer
It is not an easy job to train your dog. But once you both find a way to listen to each other you can become a dog whisperer. The main thing you should have is patience. Nothing more, just be patient and give your dog time. Don't be frustrated because your dog will feel it, and he will start hating the moments you try to train him. In the following text you will find a few tips and tricks on how to train your dog in the best possible way.
Instead of scolding, think about what you would rather want your dog to do. Focus on that and take your time to teach your dog to follow your commands. But it first needs to know what you want if you say "sit" or "leave it", so make sure to give your best to teach your dog the meanings of those words.
Whatever you are training your dog it is important to make everyone around you to get involved, especially those people who are often around your dog. Ask them to do the same as you do. Your dog will easily understand what you all want if it is more of you. For example if you are saying "off" when your dog is on the couch and someone else says "down", while others let your dog just stay on the couch, how can you expect your dog will ever learn what you mean and what is right and what wrong.
Feel free to push the limits. Once you are sure your dog has learned one thing go right to another. But you must be sure he has mastered the first level. Your dog will never get tired, and dogs are pretty smart, so you will hardly get over his limits. Just play along, share affection and give your dog treats when he deserves them!