Look at the standard tips for going to sleep earlier - relaxing, not using the computer right before bed, etc. But when it comes down to it, go to bed earlier and stop doing stuff. Even though you may not be tired, you'll get tired and fall asleep. Or not, but at least you'll relax. I know this sounds silly but I do this every time I take the red eye. I know I can sleep on it, but I still have to tell myself "even if I don't fall asleep, I just have to keep my eyes closed for half an hour". The act of having them closed gets me to fall asleep.
And when it comes down to it, admit that you are going to be tired if you are waking up two hours earlier than normal. Think about how your body reacts to that. For example, if it takes you an hour to be functional, get up an hour earlier than you need (as painful as that may be.)
For work, it is easier because it is regular and you can shift. For a one time appointment, you are quite limited in what you can do.