I started drinking at an early age and through the years, I've learned that the best cure for a hangover is following steps to not have one in the first place.
1) Don't mix drinks. If you start with vodka, keep drinking vodka until the night ends.
2) Drink water often during the night and when you get home.
3) Eat small bits throughout the night.
4) Have a good dinner before you start drinking.
5) Find one drink that doesn't give you a hangover and make it your new regular drink. Champagne kills me the morning after, so no bubbles for me. Heineken is the one beer that will never give me a hangover. Good scotch does it for me too, since I'm drinking water from the melted ice and hydrating my body as I go.
Thats about it. Never worry about a hangover again!
Call me master of the obvious, but this is the method I use to be able to be productive the day after and it works.