Unlike the chitchat of everyday life, dialogue must express character, advance the story, suggest a theme, and include a few memorable lines that audiences will be quoting for decades to come. The best stories have dialogue that sparkles, but it’s easy for inexperienced writers to fall into common pitfalls like creating dialogue that’s wooden or too on the nose. Other writers end up with exposition awkwardly inserted into conversations, actors tripping over unnatural phrases, or characters...