If in doubt, ask directly: What is the story you want to tell? What's your angle? And what do you expect from me? Your questions put the journalist under obligation and even out the balance of power.

In simple terms, TV journalists have three different kinds of sources in their stories:

• The case = a "regular person" who ensures identification with viewers. The case gets a lot of airtime
• The helper = must support the credibility of the case or story. The helper is often allowed to deliver 1-2 statements
• The opponent = the bad guy. The opponent gets significantly less speaking time than the case

Which one are you? Find out in advance.

Ask the journalist who else is in the feature. The answer can tell you if the journalist has a hidden – critical – angle. Remember to ask again when the journalist is in front of you immediately before the interview. There may be new players on the field.

You'll get 8-10 seconds of speaking time – maybe 20 seconds if you're lucky – in the final feature. You don't get to decide which bit the journalist selects from the interview, but you can narrow the selection by choosing a maximum of three messages you want to get across – short, clear and to the point. Also, you can make it harder to edit your speak if you incorporate the journalist's question into your answer.

Once you've agreed to an interview, prepare for all the critical angles – even if the journalist hasn't mentioned them on the phone. The critical questions always come up anyway.

See a critical story as a chance to get your message across – not as a risk of being humiliated on national TV. A refusal to interview or "no comment" will always get you stamped as the villain in a story that will air regardless.

When you're interviewed by a TV journalist, it may have been hours since you first spoke on the phone. It's time for the final round of counter-questions:

• Has a new angle developed?
• Have any new sources (opponents!) appeared in the feature?
• Does the journalist have new expectations of you?

"Noise" makes it difficult for the viewer to concentrate on your message. It is therefore a good idea to:

• Practice the expected questions in front of the camera on your smartphone. This gives you peace of mind!
• Think about what your clothing style signals
• Avoid moiré patterns. The camera struggles to render thin stripes, check patterns or other dense patterns on clothes in a way that looks good
• Avoid clothing with logos and text. The viewer may get distracted if they can read a message or the make of the shirt
• Avoid clothes in pure red or white colours. Red clothes make the screen flicker. White clothes easily become too bright.

Television is a powerful medium because communication takes place in both sound and images. This means paying attention to how you speak, how you gesture and how you interact with the journalist and viewers.

• Avoid internal technical speak
• Take your time to answer. Pauses make you appear judicious
• Answer the questions briefly, precisely and without irony
• Keep your hands free but avoid excessive arm movements. Body language matters!
• Be welcoming

Evaluate your performance with a colleague or communicator so you can do even better next time. Even professional "telegenic charmers" practice.