Nicholas - Similar to the pilots above but I did have a system, of sorts!
Always carried ear plugs, eye shades and bull dog clips and duct tape to ensure curtains didn't let in too much light. My procedure was to get up early on the day of the flight and go for walks, do something useful if at home, generally not sit around waiting, then go to bed at least four and possibly six hours before call time after having a meal, the meal causes blood to leave the brain and go to the stomach to process the food.
Even used to go to the gym sometimes but this has to be over at least three hours before you want to sleep as the adrenaline is high after exercise and may prevent sleep.
The USAF did extensive study of pre-flight rest, meals, cockpit lighting etc. and discovered that resting in a darkened room at a reasonable temperature was about 70% as good as actual sleep, so lying there fretting about not sleeping is pointless and I found I would almost always drift off into some real sleep. I always went to local time away from home.
On board the aircraft, once settled in the cruise, ensure cockpit lighting is reasonably high, this helps to reduce fatigue, (darkness induces sleep!), keeping the whole FD dim achieves nothing as your eyes are actually focused only nine inches on the other side of the cockpit glass!