Manchester United's players can expect to be better footballers and win titles under Louis van Gaal's management. This is the message from those who have been in his teams. Beyond a sparkling CV that shows the Dutchman claiming championships at all four previous clubs, plus the Champions League, is a story of how Van Gaal's tutelage allows talent to flower.

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Winston Bogarde played under Van Gaal at Ajax, from 1994-97, and Barcelona, from 1998-2000, winning the Champions League and two Dutch and Spanish titles. "Van Gaal is one of the best coaches, he likes to play football," Bogarde said. "And he enjoys coaching players, getting the best from players. He likes to play with young players, he likes to play with young talent and developing it."

The last comment points to how Van Gaal believes younger footballers buy more easily into his methods. As Mehmet Scholl, his former reserve team coach at Bayern Munich when he led them between 2009-11, said: "Some of the players, like Rooney, I don't think he has to learn anything more. So that will be difficult for him if the coach says: 'You have to do it in a completely different way. Whatever you did until now, change it.'"

Yet a key component of Van Gaal's success is his ability to spot what players have missed about themselves, with his genius for harnessing this transforming some careers. At Bayern, Van Gaal converted David Alaba from midfielder to left-back, as he did with Simon Poulsen, when managing AZ Alkmaar from 2005‑09. "He can get an extra five or 10% from players," Poulsen said. "He made me better. I changed my position under him. I was a left-winger, now I'm a left-back and I made a lot of international games in that position. The first time he told me I thought he was crazy but it turned out to be my best position."

The Dane suggests Van Gaal's man-management skills are more subtle than the stern persona suggests. "It doesn't make a difference to him players who are not in the team," the 29-year-old said. "For instance with myself, in the beginning I wasn't playing so much but even if I had an argument with one of the players who play every game he didn't take their side. He was always honest. When you're not on the field he will come and ask you: 'How are you?'"

Bogarde concurs that Van Gaal has no favourites. "He is not scared of the big decision," the former defender said. "If for a certain match he has to bring in one player and leave out another player, he is able to take the big decisions when needed."

The United squad should be prepared for demands of total focus and belief from Van Gaal. "He plans a lot and you will know exactly as a player what you should do during a game and your opponent, how he plays," Bogarde said. "He has his own style but it depends on the players, though he likes to play attacking football.

"He commands respect and has a strong personality and he wants to do it his way, he's good at making the players do what he wants."

How do his teams play? "In his mind he likes to play 4-3-3 but he can also play in other formations, he can adapt," Bogarde said. "He will look at the players that he has and then he will adapt to that. But whatever he has it will always be an attacking play."

Poulsen said: "As a trainer he is good at looking at what he can do. He always makes sure he has a strong organisation, he wants the team to keep the ball. I think we had almost 60% ball possession."

Perhaps the most eye-catching success on Van Gaal's résumé is the title he won for AZ in 2009, which remains the second in their history. Poulsen said: "We maybe didn't have the best team but he does the best for each player and we had 24 games where we kept a zero, and we were playing good football."

So, as Bogarde adds, the message for United players is to get on-message and stay on-message with the man known as the Iron Tulip. "As long as you understand what he wants in return, he is a manager who supports his players and has confidence in his players. Every player likes to have success – he's one of the most successful coaches in the world.

"He is going to be a big asset for the Premier League."