Most dogs are smart and want to be obedient. Not giving your dog any direction or training is just asking for him to behave in a negative way. 'Stay' is a good one to teach and comes in handy in instances where otherwise your dog could run off and be hurt or get lost.
Teaching dog to stay
Large dogs do not only have a stigma attached to them sometimes, regardless of the breed, but they also are harder to control with just physical force. You should establish dominance as the pack leader over your dog in order to have control. Having control over your large dog is an important reflection on you as a pet owner and on the relationship, you have with your dog. Not only that, but no one likes being around an out-of-control dog. Training your dog will make you and your pet much more likable to outsiders.
Keep an eye on your dog and his actions. If your dog obeys, you should make eye contact, offer verbal praise and give him a treat in that specific order. An example would be that your dog sits - look him in the eye, say "Good boy, that was a good sit" and give him a treat.
Dogs are sensitive animals. Reprimanding them is usually unproductive. Instead, only offer positive reinforcement when they do good things.
The 'stay' command can be taught from three different positions: sitting, laying down, or standing. The end goal is to get him to obey the 'stay' command from any of these three.
Start with your dog on his leash and with you to his right side. Take your hand, palm forward and put it in front of his face, so that he sees it and says the command 'stay'. Now step forward on your right foot (not your heel foot, which is your left), take a step or two forward, and turn back to your dog.
Repeat the hand signal and the command 'stay' and step back to your starting position at his side. Give him verbal praise for staying (such as "good stay") and reward him with a treat.
As you progress with the exercise, you should stay facing your dog, but not beside him for longer periods of time, and then eventually, you should gradually increase the distance away from your dog that you are standing until you are at the end of his leash and standing away from him for a long period of time. Make sure to continue praising and rewarding him for his good efforts.
Remember : This is a very gradual exercise and the distance and length of time you are away from your dog should gradually increase.
You may be worried that your dog's only motivation for obeying is his treats, but this is not so. Dogs are eager to please their owners. Make sure that for this exercise you are not showing the treat to your dog beforehand and you will be fine.
Training is a slow process and as previously mentioned, most dogs do not respond well to getting reprimanded. Make sure to dog-proof your home so that there are less tempting bad situations for your dog to get into, but do stick to your guns on the small, important tricks you are teaching him. Your dog should always be willing to do a 'sit' or a 'stay' once they've learned it and if they aren't, work the exercise with them more often.
After you feel confident in your dog's ability to stay under controlled circumstances, switch up the situation. Have him stay from different positions or in different environments. Allow for distracting variables once you are confident in your dog's training without the distractions in place.