To make a difference for someone, you could do something hard for them… You could also do something to enjoy, to make them feel happy. You can give them compliments or say nice things about them to make them feel special. Otherwise just doing nice things and making them feel special can make a difference for someone.
The particular piece of music is the third piece in the composers 20th collection of works. That can included all kinds of things like symphony's operas among others.
