Nick Bollettieri: How do I spot potential? It all comes down to passion

There's no tennis coach in the world, not even me, who can make a champion unless there's talent to work with. You also need other fundamentals: a pool of players for competitive tension, top-notch facilities, excellent coaches and a clear, comprehensive programme that goes from grips to Grand Slam-winning strategy. Plus the best academic education, physical conditioning, diet and pastoral care to ensure you're producing healthy, rounded people. And you need to instil a mentality that dictates working to dropping point, and the dedication of every waking moment to your goals. That's the basics covered.

There's no tennis coach in the world, not even me, who can make a champion unless there's talent to work with. You also need other fundamentals: a pool of players for competitive tension, top-notch facilities, excellent coaches and a clear, comprehensive programme that goes from grips to Grand Slam-winning strategy. Plus the best academic education, physical conditioning, diet and pastoral care to ensure you're producing healthy, rounded people. And you need to instil a mentality that dictates working to dropping point, and the dedication of every waking moment to your goals. That's the basics covered.

Next come the four factors that I believe differentiate the simply good from potentially great. First, true self-belief. Second, the ability to accept support. Third, adaptability, by which I mean being capable on your worst day of still giving your best. And fourth, passion, which you either have or you don't.

People always ask me how I spot potential, and ultimately it's about that X-factor: Passion. I saw in it Monica Seles as a girl, so small that a puff of wind could have blown her off her feet but so intense that she played every point as if her life depended on it. I saw it in Andre Agassi, all teenage pigeon-steps but eyes that spoke of gifts bestowed by The Man upstairs. I saw it in little Maria Sharapova, nine years old but with ice in her veins.

You can't be right all the time, but if you have confidence, and convey it, self-belief is self-perpetuating. How else can I explain why Serena Williams chose to come to me for a week before each of her five Grand Slam wins in 2002 and 2003? What could I teach her, one of two of the finest female athletes in history (the other is Venus) about playing tennis, except advising a bit of work on her serve, her volleys? She arrived saying she was tired of being No 2, I convinced her it didn't have to be that way.

Accepting support is crucial and I now know how best to be supportive. You listen. Andre taught me that way back. "Have you ever listened to anyone in your life?" he once asked me. "No, not really," I replied.

"Well you should try it," he said. "You might learn something." I tried it. I learnt. It makes you a more effective teacher.

So to adaptability, for player and coach alike. Champion athletes have bad days and still win. The right training, to breaking point at times, helps. And the coach needs to be adaptable too, to address the paradox of needing to treat every student differently, but every one the same.

The same in terms of attention and detail, whether they have $50m in the bank or zilch. Different because no two players are alike.

At one point my resident students included David Wheaton, who rose to be world No 12, and Jim Courier, Monica and Andre, who all made No 1. David's mom was a born-again Christian who stood on the sidelines and prayed on every shot. Jim was a workhorse, a battler.

Monica, the Postage Stamp, stuck until she got there, practising a single shot for 12 hours at a time. Andre? Jeez, I thought: "Will he even show up today? And what will he wear?" But I got to know what made each of them tick and I wound it up.

I'm a lousy businessman. I had to sell my academy to IMG in 1987 because I was going bust, I'd given too many scholarships. Do I regret that? Never. I want the best from myself, I want the best from my students. I want them, like me, to give every hour of every day to their goals.

I'm 74 next month, which I figure means I have perhaps only 50 more years at the frontline. But still you have to treat every day as though it's the only one that counts. That's what drives me. Life can be gone in a fraction of a second. I've known that ever since my brother, Jimmy, died in a freak accident, aged 14. Do what you believe in. But do it today. It has to be today.

Nick Bollettieri will be writing for The Independent throughout Wimbledon