A: There are many things you can do to improve your mental performance.
A clear mind is supported by a clean diet. Eliminate all processed and refined foods and replace them with unprocessed whole foods like whole grains, nuts, seeds, fruits, and vegetables. Your diet should include brain boosting omega-3 fats found in flax seeds, sesame seeds, walnuts, and fish.

Next, be sure to care for your liver. If your liver is congested your mind will feel foggy making it hard to focus and concentrate. Fried foods, alcohol, cigarettes, coffee, excess fat intake, late night binge eating, refined foods, stress, and anger all congest liver function. To keep your liver happy, eliminate these stresses.
Certain herbs can enhance memory and concentration. Ginko biloba, gotu kola, Siberian ginseng, rosemary, and bacopa are all helpful. Both Gaia herbs and HerbPharm make good brain tinctures. They are inexpensive and easy to use.
When I was in school I found aromatherapy worked wonders. The sense of smell acts directly upon the nervous system to wake you up, relieve mental fatigue, enhance concentration, improve focus, and aid memory. Simply carry a small bottle of essential oil to smell in class and when studying. In addition, using a single scent for a single class will create an association between the scent and the subject. In the future, whenever you smell that scent, your memory of the subject will be enhanced.

Your mind will also benefit from a regular meditation practice. Meditation reduces stress and improves concentration.