As a business writer, myself, allow me to add a few things:
One very good point was knowing your reporter. The personality of every reporter is different. Take me, for instance, I am very laid back, conversational and I like to shoot my questions from the hip. Other will show up with a list of questionbs, will become annoyed if the conversation goes off course and will trap you if they think something stinks.
"Shooting from the hip" can be good. But be sure that it is informed. If you don't feel comfortable answering a question because you're not sure you know the answer, ask if you can double check the information and answer the question later. Reporters want accurate sources.
Don't push your agenda, slide it in. If you are stressing to get in points, the reporter - even a laid back one like myself - is going to get irritated. Remember, we have the highest level of editorial discretion in this process. Good reporters will recognize when someone is trying to use them to fulfill their agenda. Not only will that portion of the interview be ignored, your shot at another chance with that reporter will be gone.
Do prepare. Prepare like you were making a business pitch to the most important client you have ever had. Know your stuff inside and out.
I saw someone else mention about not going "off the record." Unless you know the reporter and have extablished a level of trust - don't do it. Even if you say it's off the record, some reporters will run with it. I can't stress that enough. Believe me, this industry is filled with a bunch of people looking to make names for themselves.
Don't be nervous. Something else I can't stress enough. After all, you're going to be talking about your business and line of work. That is a subject you should be enthusiastic about and enjoy discussing. Keep in mind, while there are a few bad seeds, the majority of reporters aren't out to get you - they're out to get a great story.
Be willing to share about yourself - more than just your business life. Reporters - especially business writers - are always looking for a way to humanize their stories. Writing about numbers and technical jargon is boring. And reading stories about numbers and technical jargon is boring. People are interesting. Don't be afraid to share a little about yourself.
One final thing, look at this as an opportunity to establish yourself as an expert. One thing writers are always seeking is someone who can speak intelligently on certain topics and add opinions that are informed and well developed. Most importantly, they're looking for someone who can do those things and will return a phone call at some point over the course of a few hours - not a few days. When the interview ends, hand the reporter your card and let him or her know that if in the future they are looking for someone who can comment on such topics, they can give you a call. This can go a long way in building "top-of-mind" recognition for your business.