A well-told story can make an abstract benefit feel real and specific, but only when it stays tightly connected to the actual argument you're making.
Choose a Story That Mirrors the Reader's Situation
A story where the reader can see themselves in the protagonist's starting position builds far more identification than a generic anecdote.
Keep the Story Proportional to Its Purpose
A long narrative in service of a minor point risks losing the reader's patience before it ever reaches the payoff.
Land the Connection Explicitly
Don't assume the reader will automatically draw the intended lesson from the story; state clearly how it relates to the offer.
Next step: Use the Sales Letter Writer to build a persuasive narrative structure into your letter around a real customer story.