Hangovers don't just happen like a headache, an ingrown toenail, or cancer. Looking for a cure for a hangover is largely too late. Prevention is the key but there are a few things that can be done to help get through the day after drinking too heavily.
Step 1: Prevention
One of the best things to do before drinking is to eat a hearty meal. If you can't do that gobble down the peanuts, popcorn, or whatever other food is available where you are drinking. Drinking on an empty stomach is unwise.
Downing a quart of water before the first drink will give your body the fluid it needs and help divert the absorption of the alcohol into your system.