If you want people to take notice of what you say, you simply need to pump up the volume. Max Atkinson (no relation) has advised politicians on both sides of the aisle and on both sides of the Atlantic about how to present information more effectively, and he has this to say about the difference between a conversation and a presentation:
"…It is through variations in tone, stress, pauses, pace, etc. that we convey enthusiasm, passion and emotion. The trouble is that many speakers deliver with much the same intonation as they use in conversation, not realizing that conversation is a short distance mode of communication. Across a meter or two, co-conversationalists can pick up slight inflections, emphases, etc. But across the longer distance between speakers and audiences in presentations, the slight inflections flatten out and come across as a monotone. Effective speakers therefore have to learn to exaggerate the intonational patterns they use in everyday conversation, if they want their enthusiasm and passion to travel across the longer distance to the ears of their audience."
I’ve noticed exactly the same thing at my local speaking club, especially when it comes to yours truly. I’m normally a pretty even-mannered guy, but when I speak publicly, my words tend to come across as a monotone. I notice the same thing with the majority of other presenters. My own resistance to greater inflection is that I don’t want to come across as being fake or cheesy. But Max’s perspective above makes sense – a presentation is different from everyday conversation; it’s a specific and special type of communication that demands greater intonation than normal. That’s not to say that you can’t use informal language as opposed to formal language – the point here is the way you use the words you naturally speak.
Tip: The next time you give a presentation, try doubling the amount of enthusiasm you think you need to have, exaggerating your tone, stress and pauses. Afterward, have a conversation with some members of your audience to see if your presentation communicated the enthusiasm you intended it to.