48 hours before:
Stop all supplements (but keep taking prescribed medications)
Avoid alcohol completely
Avoid rigorous exercise
Start hydrating: at least 1/2 your body weight in ounces every day
Aim for 7-9 hours of quality sleep
12 hours before:
Fast completely - only water is acceptable
No snacks or other beverages, even diet beverages, black coffee, or tea
Morning of the draw:
Drink 16-24 oz of water
Do not drink other beverages, even diet beverages, black coffee, or tea
Wear short sleeves or easily rolled sleeves
Prep a snack or meal for after the draw