How many speakers watch the nightly news programs and applied what they learned to their presentations? The key point that you can take away is how fast the announcers go from one story to the next. Stories are compact, short lived and quickly grab your attention. In a space of 30 minutes, you may have many stories.
The danger of not constantly holding your audience’s attention is that they may mentally use their brain as a remote control and zap you to the next channel. This maybe simply just daydreaming or looking at their smartphone.
Your forty-five minute presentation may be one topic, however think in terms of five to six minute scenes. Each scene is built around your points and sub-points. Also in each scene there is a sentence that you deliberately inserted to direct your audience to what you want them to take away.
Learn from the best, to make your presentation the best.