go here to listen--there's a key to help you recognize which NPR hosts and reporters are reading various passages--and since the text is there, you can read along with them.
Practicing delivery is easier with a well-known text that's not your own writing. All the better if you're using a familiar text, as this one is to most Americans--that lets you focus on emphasizing particular words and phrases, pacing, cadence and other vocal qualities.
Once you've done a read-through, listen to what the NPR team chooses to emphasize. What vocal qualities are they using? Do they work to put the words across?