Back in the old days at McKinsey, your interviewing skills as a consultant on a team would be evaluated roughly on 3 levels: 1) you got the piece of information you needed (the market for [x] is $1bn, 2) you managed to get an insight that was completely new to the team, and 3) you actually made the interviewee realize something she did not know before.
Great journalists know exactly what questions to ask at what time in the interview. The interviewer draws out the story of the interviewee.
When designing a presentation think of your self as the interviewer. If you design something for someone else, then you can take it literally. If you design something for yourself, imagine interviewing yourself in front of a big audience.
Poor interview question: what five pieces of research support the assumption about the target market size? Good interview question: what, I thought only 5 people need this product, give me a feel for why this thing is huge? Poor interview question: "Now that we have spent the past 30 minutes analyzing the market, let me ask you: what do you actually want to achieve?" Good interview question: "before we dive in, tell us quickly what your ambition is". Poor interview question: "So let me re-phrase what I think your story is". Great interview question: "But is your story not a bigger one if we draw the parallel with this?"
Then you will have hit level 3, the interviewee walks out of the chair with a different perspective, and the re-designed presentation will be more than a beautification of existing slides. Which interview do you want to follow to the end, and which one will you skip with the mouse or remote control?
Image of Larry King and Vladimir Putin from Wikipedia