Be sure to respect your audience by keeping information simple and easy to digest. And perhaps the best way to know whether another person or audience is tracking with you is to make time for questions.
Q&A is a good way to calibrate with your audience to determine whether you need to revisit a particular point or be clearer about why it is that they should buy in to your position.
Pathos - this refers to the emotional hooks that connect an audience to the position you want them to adopt. Sometimes people will use fear, or the threat of something de-stabilising, to get people on board. Politicians often rely on fear as a way of getting buy-in.
Other times, people will create a compelling picture of a different and better future that people really want to be a part of. The emphasis on the positive, rather than the negative, creates a different energy about moving forward.
At work, we want people to think of the work they do as being about something bigger than a bi-weekly pay cheque. People spend many long hours each day and week at work, so it's important to think about how to connect their work, or the company's work, to something bigger than just making money.
The famous story about the janitor at NASA telling people that his job helped put a man on the moon is but one example of how people feel a deeper sense of connection to their work if they believe it's about something important and meaningful.
Most importantly with pathos, people have to sense that you PERSONALLY have an emotional connection to what you're trying to sell them. It's hard for you to ask others to buy in emotionally to something if they sense that you haven't done the same.
Ethos - this refers to your credibility and whether people believe that you have 'earned the stripes' to make you - and your argument - believable in their eyes. If an auto mechanic recommends a certain toothpaste, you probably won't take his advice over that of your dentist, just like you would not let that same dentist tinker with your car before you drive it across a long and barren stretch of road.
Don't assume that the audience knows your background or the different experiences you've had that give you the credibility to make a case. You can make reference to particular personal experiences and examples and, in some cases, you may want to cite best practice or other references that tell your audience that you have sufficient expertise, which then makes it easier for them to buy into your business case.
While you don't want to over-sell your credentials, you also don't want to leave the audience in doubt about whether or not you've got sufficient experience. Find a way to build your ethos as you also build your business case.
All Three Proofs Together
The best way to persuade people to take a certain position is to use a combination of all three proofs. There's an old adage in business that says you have to 'win the hearts and minds' of the people you're leading. We often over-rely on logic and underplay the emotional connection that people sometimes need to buy into something new. And even with those two bases covered, it all falls apart if they've ruled you out as 'credible' even before you start talking!
If your goal is to be more persuasive at work, Dr. Aristotle's three proofs will likely serve you well.
Harold Hillman is a business leaders coach and author. He has a Master's Degree in Education from Harvard University and a Ph.D. in Clinical Psychology from the University of Pittsburgh (USA).
Previous roles include Corporate Vice President & Chief Learning Officer at Prudential Financial (New York). Hillman came to New Zealand in 2003 to join Fonterra and is now the MD of Sigmoid Curve Consulting Group, where he coaches business leaders and executive teams. His latest book is 'The Imposter Syndrome". 
