The author should also consider their personalities. Harry is brave and sometimes impulsive, while Hermione is intelligent and logical. Their relationship could grow as they learn from each other. For example, Harry could learn to think more before acting from Hermione, and Hermione could learn to be more spontaneous from Harry. Also, adding in some conflict related to their different approaches in life can make their relationship more real. Maybe they have an argument about how to handle a situation at Hogwarts, but then they make up and realize they care too much about each other not to be together.