Write the proposed incident at the top of a page, then list the next three important actions taken by the protagonist. Draw a causal arrow only when one action genuinely results from the incident or from a consequence it created. If the following chapters would unfold almost identically without the incident, it is probably atmosphere, foreshadowing, or setup—not yet the event that launches the central problem.
Next, separate the inciting incident from the first-act commitment. They may occur in the same scene, but they often do different work. The incident disrupts the existing life; the later commitment establishes how the protagonist will respond. A detective receives the missing-person case, then decides to conceal evidence from a superior. A young heir learns the king has died, then accepts a politically dangerous marriage. The first event opens the problem. The second closes the easy route back.
Suppose a fantasy opens with a courier seeing a dragon above the capital. The image is dramatic, but it is not automatically an inciting incident. If the courier completes the delivery and the next chapters introduce the court, the dragon is only a signal. Make the dragon destroy the bridge carrying the courier’s brother, expose the royal seal hidden in the courier’s package, or force the courier to choose between delivering a warning and rescuing survivors. Now the event changes responsibility and creates the next action.