Like some others have said, drink water. Gatorade helps a lot too. Alcohol itself is a diuretic, meaning it makes you piss a lot, plus throwing up pretty much finishes the job. Your body ends up with less water than the Sahara. Much of the symptoms of a hangover are caused by dehydration, not the alcohol itself. I remember seeing a comedian a while back saying how he read about somebody dieing of dehydration and how it would be a terrible way to go. Imagine a hangover so bad it kills you.
Next time you drink, drink a couple of big glasses of water when your done and if its night time drink a real big glass just before you go to bed/pass out. You'll wake up feeling a lot better.
