I think I read about a guy on Reddit who conditioned himself to become an early riser. In the past, he would repeatedly hit 'snooze' and sleep in. His method was to practice waking up. He did this in the evening by matching conditions to his intended morning wake time (i.e. wear pajamas, turn off the lights), set his alarm for a few minutes in the future, lay down, and wait. When the alarm went off, he would stretch, stand up, stretch again, and begin his typical morning routine.

After enough practice runs, the poster claimed that in the morning he would automatically rise when his alarm went off and begin his morning routine. He claimed that he didn't really fully wake up until later.