Water
Students need to drink a lot of water. A hydrated brain learns better, organizes better, and thinks more clearly. Students should always have a water bottle in class.
Sleep
According to WEBMD:
"Sleep is the power source that keeps your mind alert and calm. Every night and at every nap, sleep recharges the brain's battery. Sleeping well increases brainpower just as weight lifting builds stronger muscles, because sleeping well increases your attention span and allows you to be physically relaxed and mentally alert at the same time. Then you are at your personal best."
7-12 Years Old : 10 - 11 hours per day
At these ages, with social, school, and family activities, bedtimes gradually become later and later, with most 12-years-olds going to bed at about 9 p.m.
Sleep needs do not decrease and remain vitally important to your child's health, development, and well-being. Without the proper amount of sleep, your child will become increasingly sleepy during the day. Those children with a history of sleep problems see them persist. They do not "outgrow them."
In his book Healthy Sleep Habits, Happy Child, Marc Weissbluth, MD, sums up what you may find in children who routinely do not get the sleep they need, with a bit of a Catch 22: "School achievement difficulties were found more often among poor sleepers compared to good sleepers.... Young children who have difficulty sleeping become older children with more academic problems.