Here is some advice that I have learned from my experiences, cousins, and
articles (in published journals and magazines):
1. Don't drink too many sugary drinks, as a hangover from sweet drinks is a
lot worse than those from hard drinks (i.e. vodka, gin, rum, etc...)
2. As you start to move from buzzed to drunk, start consuming less alcohol.
The alcohol that you consumed at the beginning of the night will start to
burn-off, and the alcohol that you are putting into your system will diminish
the effects of a soon-to-come hangover (obviously a hangover will ensue, but
it will not be as long or intense as it would normally be).
3. Towards the end of the night (probably the last drink or so), drink a
spicy, non-alcoholic drink (even if you do it at home). Spicy drinks (and
food) help to open the arteries, get the blood flowing, and help filter the
alcohol out faster (read that one in a true article).
4. A saying (not necessarily true, but fun to say):
Beer before liquor, never been sicker. Liquor before beer, you're in the
clear.
--Like I said, not all of this is proven fact or research, but it might help.