Changing our sleep habits can be challenging. I suggest setting a goal (a bedtime of 10:00 p.m., for example), and then developing a personalized strategy to reach that goal over time. It may help to stop using your computer or cell phone an hour before turning in. Also, try turning the thermostat down -- a temperature of 60 to 67 F is best for sleeping. Pay close attention to how you spend your day, especially in the evening, to determine how you could rearrange your activities to allow for an earlier bedtime.
Moving your bedtime up by a half hour should be doable fairly quickly, but if you’re moving it up more than that, expect the transition to be gradual. Everyone has an internal biological clock that impacts their ability to fall asleep, so making small, incremental changes over the course of several weeks is most realistic.