Vyris had some great advice....and I have some more to add. Take it from a pro (6+ years in the Navy, a number of years as a bartender, and many gigs at local dives later)...
1. Don't drink rotgut - the impurities in the alcohol will add to your hangover. 2. Don't drink mixers that contain tons of sugar - the sugar content will add to the dehydration effect which is what really destroys you the next day. This is why people always say to drink water before going to sleep after a night out. If you can minimize the dehydration, you will end up feeling TONS better the next day. 3. A prime drink is whiskey/bourbon and water. It will get you worked, but will leave you feeling a lot better in the morning. If you drink the really good stuff, and get a taste for it, you can even become a connisseur. 4. If you are drinking beer for quantity, not quality, the cheap, closest to water garbage is the best - see note 2 above. 5. If you want to drink the best tasting beer, go for Guinness, hefeweizen, any of the Trappist ales, or try some true English bitters...however Guinness and the English bitters really don't travel all that well, so I'd advise a brewery expedition to England and Ireland for those. Every area in Northern England worth its name has its own local bitter. 5.5 When drinking the cheap beer, I heavily recommend "Red Beer", which is an ice cold beer mug, filled about 1/4 of the way with tomato juice, topped with beer and then a dash of salt. It is a wonderful concoction that helps with hangovers. 5.5.5 The above drink works VERY well as a hangover cure. Old salts call it "The hair of the dog that bit you". If you have a drink in the morning when you wake up, just ONE drink...don't get drunk again, it will help the hangover smooth itself out in the long run. 6. When buying alcohol for the house, stay away from the store brand (see note 1 above) but also don't waste your money on the top of the line junk as well. You will be fine with the upper middle price range for flavor, style and hangover help.
I have a few more that I'll post as I think of them.
The absolute BEST advice given so far however:
Never drink and drive!
Take a cab, have a designated driver, walk home...even if it takes you all bloody night, even sleep it off in a dark alley if you have to. Also, never get into a car with someone else that has been drinking - ever. No matter how convincing they are with all of the "No really - I'm fine...I only had a few drinks...give me your keys...I'll drive us home". That's just asking for you to be tossed out the passenger window as your car rolls 5 times on the local "S" curve.
If you ever do have an accident, and lets just say for arguments sake it was in Japan, and you happen to take out a guardrail and then a very small grove of sacred Japanese trees, don't ever think you'll get away with it if you walk away from the scene. Be a man, stand up and admit you were an idiot and take your punishment. It will go much easier on you that way.
Oh...and if you're drunk, and walking home as mentioned above so that you don't drink and drive EVER, don't make the mistake of assuming that the crowd of young men gathered around the local convenience store at 3 or 4 in the morning are going to be buddy buddy with you. It will NOT work out in your favor.
