Be distinctive. Find the guests who have not already been in the media and who have great stories that help define your place
On the other hand, don’t be afraid to seek high-profile guests who can advance a story or draw listeners based on their name alone. Be sure they still have a sufficient connection to your show’s mission to warrant having them on.
Don't be afraid to be provocative and to feature live discussion with sharply contrasting viewpoints. Mix it up.
Identify a clear role for each guest. When your guests all agree with each other why are they all on?
Three guests at once are generally too many. It's generally too hard for listeners to keep track of who's who, and multiple responses to questions bog down the discussion. If there are three or more perspectives that you want to include, consider spreading them out over more than one segment. Other tips include: Ensure each guest has a distinct role and perspective; a mix of gender and age can help distinguish between multiple guests, as can having some in the studio and some on the phone; introduce each person only as needed, and not all at once at the beginning of the segment; don’t ask everyone to comment on everything; do frequent micro-resets.
Ideally, all guests should be pre-interviewed. The primary point of the pre-interview is to find the story - find the focus, and to determine if the guest will be a good guest. Remember that the pre-interview is not the interview. Don’t spoil the spontaneity for the host and the listeners.
Write a focus statement for every guest that articulates why the guest has been selected and why listeners will care.
An example of WUNC Guest Booking Guidelines