Making weight on the day of a comp

I'm competing on Saturday and due to the large weight class of 65 to 75kg I've been dropping my weight down to under 65kg. I've dropped by calorie counting and upping the exercise.

My question: what is the best way regarding eating and drinking on the day of the comp? I don't want to be fatigued due to undereating and dehydration, but I also don't want to overdo it and tip the scales! This is the first time I've decided to drop a weight class and any tips are greatly appreciated!