#4 Give more game time to the bench players
One of the hallmarks of Zidane’s best season as Real Madrid manager (2016-2017) was the quality the team had coming off the bench. The likes of Isco Alarcon, Marco Asensio, James Rodriguez, Alvaro Morata, Mariano Diaz and Mateo Kovacic provided an unbelievable strength in depth to the envy of many first XIs across Europe.
The French manager didn't manage these players effectively enough to make them feel wanted. This led to agitations for moves away from the club - Morata, Diaz, James (loan to Bayern) all moved the following season.
With an abundance of players to choose from in his second stint, Zidane will need to be smarter in how he makes use of the very large squad (at least 25 players) he will have to choose from next season.
8 players or more are expected to move (sales and loans) before the transfer window shuts down in September. This will still leave a very talented squad of 25+ players to choose from.
Zidane will need to keep the squad happy. With 3 competitions to look forward to, the manager and his backroom staff will have to take up rotation as a matter of necessity.