Gerard Houllier says Zinedine Zidane must manage all the egos in the Real Madrid dressing room if he is to succeed as head coach.
Zidane was appointed as successor to Rafa Benitez on Monday after 18 months in charge of Real's reserve team.
It is his first full-time managerial job and he will inherit a star-studded squad, including Cristiano Ronaldo, Gareth Bale and Karim Benzema.
"He'll need to understand the different types of egos, the perfectionists, the flighty ones, and the winners," said former Liverpool manager Houllier, who has been managing a Liverpool Legends side in Australia.
"He has to move the players forward individually and the team forward collectively. His vision of play, the way he trains the players will be key.
"He must move the team forward and leave a heritage for his successor, and at big clubs the coaches don't usually last that long."
Benitez lasted just seven months before he was dismissed by Real, paving the way for Zidane to take over.
Houllier, who won five competitions with Liverpool in the 2000/01 season, believes Zidane needs to bring silverware to the Bernabeu.
"At a top club you need to leave a trace, and to do that you need to win trophies," he said. "Finishing second at Real Madrid is seen a failure, never mind finishing in fifth or sixth place."
Asked if Zidane would be able to help Ronaldo improve his game, Houllier said the fact he's been a great player himself could count.
"He could add to the game of these great players with the smallest of details, because at that level it's the details that count."