Hi my son slept at 7.30pm every night so normally I will not let him drink water after 6pm. Before sleep I will force him to pee then I will get him to repeat after me X10 times "Sleep no pass urine" . While changing his pajamas I will show (or rather let him tell me that he is wearing underwear) him that he is wearing underwear to sleep instead of diaper.
Normally I will wake him up on 10pm and 2am to release his urine. And will play his favorite music on my hp to wake him up. I don't know what is your child interest but my son favourote is HP thus he has manage to stay dry for nearly 1 mth. By the way my son is 6 yr old.
