When your child is in a good mood, try to talk to him in a nice way. Explain to him the do's & dont's. And when he did something good, praise him and give a little reward. It doesn't mean you need to give him something huge. An ice cream or a candy or even a hug or a thumbs up sign will do. Just so he will realize that he is also capable to do good things. An open communication line is very essential. Good luck!