With the possible exception of Celine Dion and Central Park mimes, nothing annoys me more than packages with single source sound bites. That's when a reporter does one interview and chops it up so that we keep going back to a sound bite with the same person... over and over and over and over.
Sometimes you need a second sound bite from an interview subject, but there's no rule that says the person has to be on camera for bite #2. Since nothing is more boring than a talking head, you can avoid this by covering some or all of that bite with b-roll.
Example: You're doing a package on swine flu. You've interviewed a local doctor and you are going to use two sound bites from the guy.
First bite (on camera): "We're hoping to get enough vaccine to treat all the young people in the school district."
Okay, now you have to go back to the guy who is going to talk about why young people need to be vaccinated.
Second bite: "Kids in school are in close quarters, and many still go to school when they're feeling sick, so it's easy for the flu to be transmitted in the classroom."
So, instead of showing the doctor's face again, why not cover that bite with classroom video? It's simple, makes your package look better, and it follows our "show and tell" rule.
When shooting your package, always make sure you have enough b-roll. If you hear something during your interview that might be covered with video, make a mental note to get b-roll that's appropriate.