This on'es a no-brainer. Alcohol is incredibly dehydrating, which causes those morning-after shakes and headaches. Ideally, you should be consistently drinking water while you're boozing—but that's easier said than done. “At the end of the night before you go to bed, you can get distracted and forget to," notes Bajaj. "When it’s earlier in the night and you haven’t started drinking yet, that’s a good time to drink water."