I am terrible with staying hydrated. But mostly drink water or an arnold partner. For 2017 I want to a better job and will be looking at some sort of supplement or electrolyte tab.
Water is my go to. For the last year I've consumed at least 1 gal of it every day. I use snacks like almonds, PBJ, beef jerky, crackers/cookies to provide other sustenance on the course to help with energy so I avoid the sugary stuff that can cause spikes and big drops of energy from the sugar.
I usually freeze a 32oz Powerade or Gatorade the night before. The humidity down here it will break apart pretty quickly and last most of the round. If I don't have that, I bring my Yeti and fill it up with ice and water.
I usually do water as it's easier to just keep refilling on the course in my tumbler, I've used a few different supplements over time, bio steel is the latest.