If your dog does jump up at you then don’t react at all. You should stay calm, quiet and wait for them to stop. You can then reward them when all four paws are back on the floor. Your dog needs to learn that they won’t gain anything by jumping up. Instead, it’s keeping all four paws on the floor that will get your attention. Make sure you reward your dog with praise when that's the case, especially at times when they’d be most likely to jump up. You can prepare yourself by making a list of all the situations in which your dog might usually jump up. Be quick to interact with them before they do.
Don’t tell your dog off for jumping up, as discouraging your pooch from jumping up by telling them off or saying “no, get down” could be rewarding for some dogs as they are getting attention. Do persist with your training, whenever you stop responding to any behaviour the way your dog is expecting you to, they’re likely to try that same behaviour with greater intensity. Consistency is key, if you’re consistent, your dog will quickly learn what works to get your attention and what doesn’t.
Teach your dog to sit when meeting people, ask a friend or relative to walk towards you and your dog, when you get close to them, stop a short distance away and ask your dog to sit. Have some extra tasty treats ready to reward them with, continue to reward your dog for as long as all four paws remain on the floor, giving them a treat every now and again while you talk to your helper. If your dog suddenly becomes excited and jumps up, make sure you don’t engage and simply stay calm, quietly waiting to reward the moment they stop bouncing.