Preventative: Drink Up… The Water
This might sound like an obvious trick, but most underestimate it. Perhaps if you knew the science behind it, you would be more inclined to participate. Since alcohol is a diuretic (makes you use the restroom often), drinking it contributes to dehydration.
Dehydration isn’t a main cause for hangovers, but it does contribute to thirst, fatigue, headaches, and dry mouths. All the symptoms that come with having a hangover. Do yourself a favor and drink enough water before your night out and in between drinks.