Ok, here is what you do. All hangovers are preventable, but once they occur there is not a lot you can do. Lets start with what happens when you get a hangover and work backwards to prevention and causes.
When you get a hangover the best thing is coke. Sorry if you don't like coke, but it really is. It has caffeine which eases your body out of the lethargy of a hangover, it settles your stomach, and is easy as hell to throw up. Water is also obviously key. The two types of hangover are from dehydration and vitamin deficiency. Dehydration causes headaches and deficiency causes you to want to puke. Painkillers are virtually useless if you have both types of hangover because your body will almost certainly reject them, and if you haven't eaten since that kebab you chowed down on at 3 am, they will usually have an adverse affect. Don't bother unless you just have a bit of a headache and need to function. Drink some coke, then drink some more water. If you have to puke, puke and then drink more water. Thats it. Thats all you can really do. Greasy food will help but either get it in early or don't bother because hangovers get worse and worse as time goes on typically, and you'll just wind up throwing it back up almost immediately and throwing up barely digested food is fucking NASTY. In theory, eating foods rich in vitamin B will speed up the recovery from the nausea of the vitamin deficiency but I have never noticed much effect.
Ok onto prevention. The first tip is obviously the simplest one. Drink water. Drink as much water as you do alcohol, ideally. Water is really easy to drink and its good for you, and is free in most places. The second tip is somewhat more contentious, but has proven invaluable to me. Drop two berocca into a glass of water before you start drinking, keep up the water consumption throughout the night, and then have another berocca before you pass out, or when you wake up if that isn't possible. If you can do these two things you can basically drink as much as you want and wake up feeling much more functional than you have any right to be.
Onto causes: there's a lot of myths around what causes a hangover.
Things that DO cause a hangover:
- Drinking alcohol. DUH
- Drinking really poor quality alcohol. I'm not talking like just dirt nasty scotch, I'm talking about some grain alcohol shit your cousin brewed up and tested out on you. If you drink this shit even in small quantities, you will almost certainly get a hangover unless you are extremely vigilant with the methods described above.
- Drinking without a good meal in you first. Eat before you drink. You'll be able to drink more and you probably won't black out and leap onto the hood of a car stopped at a red light screaming "OUT OF MY WAY, CUNTS"
- Drinking really sugary drinks
Things that do not cause or exasperate a hangover:
-Drinking different types of alcohol. This is a complete myth. There's no science behind it and if you have an anecdotal experience involving switching types of alcohol you probably just drank too much of each. It can be hard to keep track of standards if you are switching between alcohol.
That said, I have been told that there is no actual reason why some alcohols would cause a hangover over others if they aren't just brewed in a bathtub, however I will always get more hungover on beer or red wine. Other people have related similar problems, but for every person that agrees, another person will have another type of alcohol that specifically gives them a hangover. Honestly, just follow the preventative tips I talked about above and it shouldn't be a problem anyway.
Hope this helps.