Start the day well rested, fueled and hydrated. You will need to spend several hours in the saddle on a century (100 mile) ride. In my case, it takes me about 7 hours to complete a century. So, it stands to reason that my body needs more fuel than most days.
I eat a good dinner and get plenty of rest the night before. In the morning, I start drinking water when I wakeup. My goal is to drink at least a full water bottle or more before the start. I also eat a solid breakfast with both faster burning carbohydrates and slower burning proteins and fats before I start riding a century.
Only with a well rested, fueled and hydrated body am I is ready for the challenge ahead.