Contrast Scrooge’s old Christmas celebrations with those of the Fezziwigs.

By "old Christmas celebrations" do you mean prior to him working at Fezziwig's? In Stave Two we see Ebenezer Scrooge sad, lonely, and brooding at boarding school over the Christmas holidays. His father wanted him to stay at the school over the holidays. We can contrast that with the merriment and love in Fezziwig's Christmas party.