Drink lots of water it kind of helps but stay off sugary drinks when you get in like orange squash as that always makes me sick if im drunk. Try not to drink spirits as well they make me very ill, i dont know about others
Or before you go out drink milk and eat a good meal, usually works for me.
It really depends how hard you're hammering it though, and what you're drinking... if you're very very very drunk then you've just got to deal with the consequences! and spirits are the worst...i only have hangovers when i have been drinking spirits...so stick to the vino! (or beer)
drink a bucketload of water, and have another bucketload next to your bed so when you wake up, you drink that. then brush yuor teeth five times in a row, have a shower, have another shower, eat a massive fry up (put everything in your fridge in a pan and heat for 5 minutes, and eat). then drink another bucketload and go for a walk. by now, 4pm, you should be feeling good and ready to go again.
As a general rule, the darker the drink, the worse the hangover (and intoxicating effect to some degree). Many drinks contain more than ethanol (generally considered the main product in inducing drunkenss/hangovers), namely congeners. These congeners include histamine, polyphenols and other complex organic molecules and methanol. Humans metabolise methanol similarily to ethanol but there is a different end product- which is more toxic than the acetaldehyde derived from ethanol. Ethanol, however, inhibits the metabolism of methanol (I think we did something on this in biology about people who have inadvertantly swallowed antifreeze being given ethanol in hospital (!) to inhibit the metabolism of methanol...) this is why people often find a swift, strong drink the morning after alleviates hangover symptoms! Therefore if you stick to pure ethanol vodka, gin or white wine, you'll escape lightly... brandy, red wine, rum and whisky may result in you reaching for that "hair of the dog" the morning after!!