I'm pretty sure the biggest change which made me an early riser was my diet though. I stopped drinking sugary drinks and cut out carbs almost entirely after midday. Diet is mostly meat, some dairy (but lactose intolerant). I only drink water or zero-sugar drinks after midday too. I drink Coffee as soon as I wake and only up to midday.
I no longer work the same job, but I still wake up around 0430 every day and do a couple of hours programming before I go to the gym for an hour, then have breakfast at 0800.
Also stopped watching TV before sleeping. When I do watch TV in bed I feel like shit in the morning. Now I turn off the screens around 2000 and am in bed by around 2200. I rarely watch any TV anyway, but still spend a large part of the day at the computer screen.