Eat a good sized meal with meat and bread before you start drinking. Don't mix drink types (or at least limit it.
http://www.youtube.com/watch?v=7g0AJPqKybs) DO NOT drink anything red or orange because if you throw up you won't may not know if it's blood or the drink, better not have to be freaking out. Drink water after every 2 drinks of alcohol. I have found the drink Rehab good if you have a hangover. Energy drinks may work almost as well too. If you have a hangover though, drinking more in the morning often makes it better because a hangover is your body going through withdrawls from the alcohol, so if you give it what it wants it can help, so keep a cold beer handy for the morning!
Please drink responsibly and don't drink and drive
(you might spill it)