Your son needs lots of positive reinforcement and focus on the times when he is behaving appropriately. Draw less attention to his negative behavior. You may want to put him on a behavior contract. Evey day that he exhibits good behavior for the entire day, he gets a sticker for that day. If he has acted up, he receives nothing. After let's say 5 stickers, he gets a special treat or gets to do something special. Accentuate his positive behavior. See if this works for a wile. When he does act up, sternly remind him of the inappropriate behavior and what should have been as an alternative reaction.