Dialogue, along with prose and description, represent the 3 aspects of scene writing. Characters are either observing, taking action, or talking (sometimes to themselves). Among the 3, dialogue is unique in that it grants every character a voice of their own.
1. One conflict/resolution leads to another.
In Harry Potter, particularly books 1 & 2, the overarching conflict is unraveling a mystery, (What is hidden in the castle? Who opened the Chamber?). Within this larger conflict, the characters engage and complete numerous smaller steps, some planned, while others are unexpected. As they progress, each resolution leads to the next step in the plot.
Some stories are told from a single perspective, in a single location, over a short span of time (for example, Emperor’s Soul by Brandon Sanderson), but in general, the longer a story is, the more complex it becomes. Most novels feature between 2 and 6 different point of view characters, each with their own cast of supporting characters. They engage multiple narrative threads, spanning a wide range of locations and moments in time.
Most relationships include a social aspect, but a true social relationship is rooted in coming together to share an experience. Social relationships are based on a common interest or shared experience. A social relationship can be casual, two strangers meeting at an event, or they can be intentional, two friends who specifically gather to meet each other.
Audiences often learn about characters indirectly, through the stories other people share. Some are objective historical accounts, but others rely on personal opinions, observations, and assumptions, including stereotypes, reputations, and relationships.