Complex sentence: Head boys and head girls are usually responsible for representing the school at events, and therefore must be able to make public speeches also being a good role-model for students, and sharing pupils' ideas with the schools leadership.
Split into simpler sentences: Head boys and head girls are usually responsible for representing the school at events, and therefore must be able to make public speeches. They also serve as a good role-model for students, and share pupils' ideas with the schools leadership.