Keep away from junk food! You may consider like you deserve a treat, or that you don't have time to cook, but what you eat can really have an impact on energy levels and focus. Keep your body and brain well fuelled by choosing nutritious foods that have been proven to aid concentration and memory, such as fish, nuts, seeds, yogurt and blueberries. The same applies on exam day eat a good meal before the test, based on foods that will provide a slow release of energy throughout. Sugar may seem appealing, but it won't help when your energy levels crash an hour or so later.