Run through what you plan to say a few times before you record so you more-or-less know what you're going to say, a script or outline can help a lot. Make sure your audio is loud enough to be understood clearly, especially if you have background music. and on that note, background music makes everything sound better, just make sure it doesn't drown out your narration. And most important, use a moderate quality microphone, or failing that, you can get okay audio out of a phone.