I don't know if anyone has said this but here goes:
1. Beforehand eat some rich food, preferably fatty. Fats (such as in dairy products) help slow the absorption of alcohol. Rich food delays stomach emptying into the gut, and alcohol is absorbed far more quickly from the intestines.
The acidity of alcoholic drinks may be a problem for some people; dairy products can help with this too. If you're lucky you'll feel a lump in your stomach and not a bad hangover: that's because it's all sat in your stomach and not been absorbed. I can't remember, but I think your stomach slowly degrades alcohol too, although the liver is the major place.
2. After drinking a lot, drink as much water as you can without being sick. Alcohol is dehydrating, as is dancing, which often goes with it. The best place for this is back at home, where you can be sick if you go over the top. Being sick is good. It empties the stomach of any alcohol remaining there.
3. Make sure you have something to eat before going to bed. If you've been on a big night out you might not have eaten for a while, and you need food. See next point for the explanation. I find rich food again is good, plus a preliminary glug of Lucozade.
4. In the morning drink Lucozade or Irn Bru (flat coke or sugary coffee will do). If you've a sensitive stomach let it go flat the day before so the the fizz doesn't upset you. The sugar is important because your liver is trying to break down all the alcohols and aldehydes from the drink but the enzyme for this is also the one that is required for turning glycogen into glucose for your body to live. If you supply yourself with an external sugar source you don't need to make your own glucose (a thing that you do all the time when not eating) and the enzyme can happily be applied to detoxifying.
This is important because alcohol is broken down rather quickly, but aldehydes, which come from it, are not, and are actually more painful in hangovers.
The caffeine, a stimulant, increases blood flow to the brain. This is important because it helps wash out the aldehyde and helps rehydrate the dried-out pickle residing in your skull. The direct effect on your neurons is less important, but might make you feel like you're thinking more clearly.
That's the best way to deal with hangovers. Don't think that you're beating alcohol though. Every time you have a headache hangover you're causing yourself damage. Brain damage may be negligible, depending on exactly how much you drank, but it's very likely that your liver is suffering.
So don't drink excessively, and NEVER drive afterwards.
