The Portuguese forward has often been criticized for being too obsessed in his chase for personal glory.
But he has shown signs of improvement - assisting three times so far this season while scoring seven goals in the process.
"Cristiano used to be very selfish, but he is changing," Schuster told Punto Radio.
"He is starting to learn that you don't get anywhere by playing for yourself.
"In the past he always wanted to try the spectacular, but now he is more capable of playing for his team-mates.
"However, I am happy for him because it's better late than never. He is a great player."
Ronaldo is currently on international duty, helping Portugual to a 5-3 win over Iceland in the European Championship qualifier despite not getting on the scoresheet.