How do I teach my dog not to jump on me or other people?

The best way is to teach the dog an alternate behavior that is incompatible with jumping. For example, teach a rock-solid DOWN and if the dog understands and you've done your job teaching then the dog will be staying down and will not jump. It all really depends on how much the dog has practiced jumping in the past and how rewarding the dog finds it. I don't allow my untrained dogs to be off-leash around people or distractions that allow them to rehearse the wrong thing. (We call this management.)

If the dog has been jumping on people for an extended period of time, more time, effort, management and maintenance of the desired behavior will be required. There can be an issue of the people around your dog who don't understand dog behavior or training that undermine what you are trying to accomplish and this can make it harder for your dog to learn as well.

Bottom line, control the dog and control the dog's experiences during the initial training process and then proof that behavior in a controlled way.