You can improve the effectiveness of your story, by focussing on delivery. Including appropriate vocal variety, stage presence, drama and eye contact can go a long way. Children are good story tellers. Look at how they use their voice, hand gestures and facial reactions to convey the message. Adults have a lot to learn from them.
The next time you prepare a powerful speech, don't forget to include a story or two.
Also read: Sample Story Telling Manual Speeches