How does the author use foreshadowing in The Good Fairies of New York?

As readers, we learn early on that Heather and Morag have competed against each other since the day they met at a youth music contest in which they both played a difficult song on their violins and tied for first place. This competition and constant fighting between these two defines their relationship and foreshadows difficulties for them as the plot develops, especially when they fight rather than team up together to help themselves fix their situation.