My dad said the word “Barrymore” not as a name, but as a warning.

Stop the drama, he meant, referring to the great actor John. He said it when I hung my head or showed my temper on the ball field.

If my dad had known more about the legend, he might have dished out the name with praise because, his tough personal life aside, Barrymore can teach all of us how to work on greatness.

My friend and coach Karin Abarbanel, who blogs daily at karinwritesdangerously.com, first told me of how Barrymore, upon learning he would be playing Hamlet, shut himself up and got to work. He showed respect for the task, put in the time, and let himself be coached — all vital to practice that gets results.

As a coach, I need to hear more: What exactly did Barrymore put into the hours? What did he work on? Diving in, I checked out “Damned in Paradise” by John Kobler, who spends a whole chapter on “Hamlet.”

First, Kobler writes, the actor went to a resort in West Virginia to read the lines (and recite them on trips around the grounds). Kobler then shifts his eye to Connecticut, where Barrymore worked with voice coach Margaret Carrington. She urged him to see the play through fresh eyes. They focused on breath control, which he practiced on his walks.

One hole remains. We know what they worked on, but not exactly how they did it. A trip in a time machine could bring us back to their sessions, to sit and hear how Carrington coached. What teaching style did she use: Pound it into the brain or pull it out of the heart? What key words did she use? What tips or analogies did she offer?

No time machine can give us the answers, but the blueprint lives. Respect the task, see it through fresh eyes, put in the time, let yourself he coached. All the practice showed. Barrymore as Hamlet ranks with the best ever. My dad would love to hear that.