Some miscellaneous components are a part of a good radio interview... some of which are directly under your control, and some of which are not. They should all be noted, however. And there are a lot, so you may not want to apply them all to one radio host... just spread them out a little. They are:

BEFORE THE INTERVIEW

First, do not consider using a cell phone, ever. Make sure your land-line works good, with no buzzing or echoes. Have a backup phone available. And make sure nobody picks up any other phone while you are on your interview. Have water or something else nearby... you don't want to have to leave during an interview to get a drink.

Send the host/producer a reminder of the time/date (better yet, call them.) Do this even if it was set up by a separate booking person. More than reminding them, it shows that you know what you are doing, and hosts feel much better about interviewing someone live on-air that they think will do a good job.

Send the receptionist a stickie-note with your contact info on it that she can post up by her phone, so she'll be able to tell callers what your contact info is when they call in. And if your topic is of interest, people WILL call in later... lots of them.

Ask the producer/host if the show will be streaming from their site, and if so, where you can find it. This is so you can record it (using a tape recorder near your computer speaker, or one of the new web-audio recorders,) or so that you can tell others where to go to listen live when it happens.

Ask the producer/host if they will be recording an aircheck (a tape of the interview). If so, ask if they would like you to supply your own tape (DAT, CDR, etc.) Most stations now supply their own on CDR, but asking shows consideration, and also reminds them to tape it in the first place.

Ask if the show will be live or taped (your booking person may be able to tell you this, as well as many of the other things.) If the host takes calls, and is live, you might want to arrange to have a few fake callers (friends, etc.) who will call-in if you don't get any real calls during the interview. Be careful with this, though... stations know very well what a fake call sounds like... only do it if the fake callers are good, and only do it if it really sounds like you need calls but aren't getting them.

Ask if it is OK to announce your contact info or your site during the interview. Usually it is, but asking in advance makes for a greater chance of the host offering you the chance to do so, and to do so more often. Sometimes you get a host which (like TV does all the time) refuses to let a guest announce contact info. Asking these hosts in advance will lesson the chance of your being surprised when they cut you off. Moreover, you may find that you decide to forego interviewing with such hosts altogether (not a good idea, however.)

Lastly, ask if you can offer give-aways during the interview. Books make for an excellent give-away, as do most other moderately priced and easily-mailable products.