Got to say hydration, electrolytes, and a b-vitamin has worked well for me, but the BIGGEST factor if you can manage it, is not going to sleep drunk. If you wait it out, and go to bed mostly sober, you will be tired in the morning but not hungover.
It's been years for me since I've had a bad one, but try drinking water in between beers and take ibuprofen before sleeping. If you're still hungover the next morning then go get a great big greasy bacon cheese burger with fries and as much Coke or Pepsi as you can stand to drink. NO McDondald's or Burger King - go find a real burger place. Then, find a cold place to go and hang out for a while. Maybe sleep some more.
This, minus the Ibuprofen (I have heard the bad things about it). Water between beers does wonders for me. I just chug a glass of water between every 1-2 beers and not only does it help hydration, but it helps fill your stomach so you can't drink as fast. Then before bed, chug a glass of water. If you wake up in the night to pee, chug more water.
In essence, water water water water. As others said.
QsnotPs said:the tea statement rings some bells.
Federal Prisons just removed green tea because it detoxifies too quickly.
Next person on a bender, give green tea a try.
Excedrin and a big glass of water. The only problem is remembering to take it before passing out.