Take it right before you go to bed to see the best results, if taken during the day, you'll be hauling rear-end.
Word of warning, you will probably sleep through man made noises, like fire alarms & vehicles, natural sounds like dogs barking, people talking things like that should still wake you up though, so maybe choose a natural alarm clock sound.
Creatine may also play a role in increasing sleep especially if stressed, but little research into that side of things, what some would still consider anecdotal.