Understand what the competitor actually did. Is it a new feature, a pricing war, or a fundamental shift in user behavior? Use Porter’s 5 Forces to see if this alters the industry's power dynamics, or the 5C Framework (Company, Collaborators, Customers, Competitors, Climate) to map the broader context. E.g., TikTok's rise wasn't just a new feature; it was a shift in the "Climate" of how Gen Z consumes content.