Conversation so far:
Any interesting information?
Berry overcame several physical ailments during his football career, a fact he became famous for.
What were some of his ailments?
bruised nerves near the sacroiliac joint occasionally caused misalignment in his back, which in turn affected his legs.
How did it affect his legs?
caused one to become slightly shorter; it was not a permanent condition.
How was it fixed?
To alleviate this, he wore a back brace for 13 years in the NFL.
Did it affect his playing?
Berry was famous for his attention to detail and preparation, which he used to overcome his physical limitations.
Did he have any other physical problems?
Due to his poor eyesight, Berry wore contact lenses when he played.
Did the contacts cause any problems?
Because the lenses would often slip when he did rapid eye movements toward the ball, he tried many different lenses.
What were his best attributes as a player?
Rather than speed, he was renowned for his precise pass patterns and sure hands; he rarely dropped passes.

Question: How did he develop those traits?
Self-contained rewrite: How did Raymond Berry develop precise pass patterns and sure hands?