I swear by the fact that using specific essential oils in aromatherapy has sharpened my mental focus, allowing me to think much clearer, remember much better, and generally feel more alert.
The best essential oils to help with mental acuity are rosemary, peppermint, and basil
One of my morning routines is to smell peppermint to help me wake up. I find it works incredibly well to dismiss the cobwebby feeling I have early in the morning. In fact, I have found it to be more effective than coffee in really sharpening my mind and making me alert in the morning.
Another application is to find a mixture that works well in enhancing your concentration and focus and using it as a perfume to help you throughout your day.