Lots of water before you go to bed always helps. If you are a wine drinker try and find a wine without sulfites in it. Hard to do in the US but it might be possible if there is a local winery near you. I used to go to France from time to time on business and they love drinking wine. Never had a hangover despite all the wine drinking. I think it was the lack of sulfites and drinking the wine over a very long (by our standards) meal.
Failing in avoiding the hangover there is always the hair of the dog or my personal favorite, a glass or two of BOOST. This is a high caffeine drink made in Riverside, NJ. Guaranteed to get you wired!