A great hitter is often a bit of a fanatic: he is obsessive about his swing and focuses his thoughts and his actions on it to the exclusion of many other trivialities. And, a great hitter is often stubborn and hotheaded: he has his way of swinging and drilling and playing.
The trick is discovering an optimal blend of this hardy, independent spirit with an open-minded, receptive attitude that accommodates adjustments and improvement. A great hitter holds true to his own beliefs, and is open to experimentation. He always seeks a new, better, and more efficient way while recognizing that many of the things he tries will prove worthless and without merit. He remains undaunted and continues to seek a better path, without abandoning the bedrock principles that make him, and his swing, unique.
In this sense, hardy means “capable of surviving adverse and unfavorable conditions; able to overcome adversity and to triumph in spite of difficulty.” The Hardy Boys lived up to their name – be a fanatic and be hardy about hitting!
From November 2010, http://raisingahitter.wordpress.com