I've found from experience, that focusing hard on the time you get up helps in waking your body up at the desired time.

Furthermore, my mother let me in on this trick (her mum taught it to her, and I find that it works): Tell your pillow out loud when to wake you up. I think it's more of the same at the bottom of it (focusing on the desired waking time).

This method typically does not fail me. I have a tendency to sleep through alarms, but I almost always wake up at the target time (or a few minutes before, sometimes!). Usually, I get up then loll around or go back to bed. But that is a willpower/discipline issue.