The trick is to find out something that your ds will really be unhappy about. For my DS, timeouts didn't matter, and at the age he was hitting, taking away books really mattered. Another phase, taking away anything with sugar in it for the day really got to him. Now, it would be taking away computer time. Maybe taking away a favorite stuffed animal? For me, it was just figuring out what that thing was that will really work as a consequence, instead of getting an "i don't mind" sort of response.