Speakers often tell great stories but forget to land a clear message. A story should support your point, not be the point. Nike's "Just do it" works because it's simple and memorable, unlike rambling anecdotes that leave audiences forgetting what you actually said.
The number one mistake speakers make is that they tell a story and they don't deliver a message. The story is, is only a fraction of your whole message. Think about this. Nike will get in front of you, they'll give you a simple story. They never tell you the price, but here's what they do. The message is just do it. Most speakers want to just talk and storytell, and they give a bunch of details, but have you ever heard somebody at the end of their message and said, what was their message? I don't even remember what it was, usually because they've given too much story and not enough message. So if you want to work on your message, you want to be able to not just storytell, then make sure that you deliver a powerful message with talking points, takeaways, and a take action.
