Yesterday I had one of the worst hangovers I've ever had. My cure starts before going to bed on the drinking night: never fall asleep on while the intoxication is rising, drink a lot of water (and I mean A LOT) and keep a glass of water plus some aspirin by your bedside. Keep drinking a ton of water when you wake up again, take the aspirin, make some greasy food and grab yourself a cup of coffee. It won't save the day entirely, but it will reaaally improve it.