J.G.
When he yells, you say, we don't yell, I would like to help you but you need to use your normal voice.
When he throws himself about or hits, we say, we don't do X and then remove him from the room ---- my son gets put in his room for a TO.
Pick your battles carefully. It's all about prevention, so really make sure he has to do what you want, and sometimes reverse psychology works great.....so if he refuses to come to do X, say you want him to do the opposite. Another trick is to offer an exchange: you want X, if I give you X will you then do Y for mommy.
Distraction is our best friend, so if you see a meltdown coming, quickly offer up something else, especially in a different location. Offer to go outside or offer a cookie.
Don't ask yes or no questions. Give choices, but make sure you can live with them. They want independence, but they need limits to help them make decisions.
But really work on how he talks to you. Don't allow yelling or thrashing about. Let him throw a fit, tell him you will talk to him when he has calmed down and can use a normal voice, and then leave the room. Do not
provide him with an audience.