Only thing I drink when playing is Coffee, Tea, or Coke, all full of caffeine, which keeps my mind sharp, I have also been known to take a couple of Pro-plus tablets before a long tourney as they are over the counter Caffeine tablets that help to keep me alert and awake.
I only start to drink a couple of beers if I make the final table and want to wind down or if I get busted out early.
I never go into a tournament thinking I will win, I make myself 3 targets to go for 1st I want to beat the money bubble, 2nd I want to make the Final table, and last of all do I then start thinking about the win!
When the fun Stops, STOP!