Flavius Vegetius Renatus was a Roman who wrote Epitoma Rei Militaris somewhere between A.D 385 and 450.

His focus was on military matters. In it he wrote

"Few men are brave; many become so through care and force of discipline."

My re-wording:

"Few men are brilliant; many become so through care and force of discipline."

Moral of the story: Do the lessons, read the material, work on the labs and homeworks, ask questions before the last minute when things are due!
It takes work and discipline to get A's.