Eating the right foods, staying hydrated, and taking your vitamins and supplements are great, but adding to these regular exercise can more effectively improve your focus.
When you do aerobic exercise, chemicals in the brain are released that increase blood flow to the brain, and also affect the health of brain cells and growth of new blood vessels within the brain.
A run, jog, or even a simple brisk walk during a break from school or work can help improve your concentration as well as boost your energy level and increase your overall productivity.
Aerobic exercise, while beneficial, is not the only way to increase your focus through exercise. Yoga, itself a practice in concentration, is very beneficial to brain function. Some poses that are especially helpful for concentration are the cobra, the plow, the camel, and the tree pose.