Good reporting, whether you're doing it face-to-face or over the phone, is key to getting a story done well. And, since misquoting people can ruin your reputation, you need to make sure you do more than just ask the right questions -- you need to listen well and get information down correctly. Here are some basic rules to remember in order to develop good reporting skills.
While a reporter needs to be quick on their feet, as they might need to chase a story down quickly, you should always know your subject matter. If you do have a scheduled interview with someone, do your homework. Know the person's background and sketch out the questions you want to ask. You need to go into the interview knowing what you'd like to get out of it and, if you write out your questions ahead of time, you're more likely to stay on track.
Be Prepared, But Not Rigid
While you always want to have a plan in mind before you do an interview, don't be unwilling to let an interview go off in another direction...if it's an interesting one. You never want to let someone you're interviewing ramble on about something pointless but if the interviewee starts talking about something interesting, go with it. Recognize when someone is saying something interesting and react to that. When you're done with the interesting aside, you can always go back to the questions you prepared beforehand.
Don't Be Afraid of Silences
In general conversation people have a tendency to want to fill moments of silence with conversation. In an interview, try to avoid that. Often, if you let seemingly awkward silences go, an interviewee will fill that void with more information.