If he disobeys, then he gets something taken away. But make sure you also give him rewards for good behaviour. He needs goals
, something to look forward to. Kids need and crave praise and validation. Look for ways to praise him. If he brings home a good grade, praise him. If he cleaned his room without asking, praise him. If he's playing quietly by himself, thank him for being so good. It may take effort to begin with, but look for ways to praise him.