How we change what others think, feel, believe and do
Necessity is the mother of invention, and the necessity of persuasion means we must first discover the best way to persuade in each situation.
The first step of invention is to understand the target(s) of persuasion. Identify who they are, segmenting them into subgroups as necessary. Identify their needs, interests and goals around the persuasive situation. Include yourself in this as well!
Secondly, consider what information you need to persuade these people. Do you need hard evidence? The testimony of others? Photographs?
Thirdly, decide how you will present your evidence. In particular consider each of Logos, Pathos and Ethos. Consider also whether you need a formal setting, such as a courtroom, or something informal, such as a walk or a discussion in the bar.
Finally, consider the context, timing and duration of your argument (also known as kairos). A long argument is necessary in some cases, but will tire people and 'unpersuade' them in others. Sometimes a person is best spoken to in the morning. Sometimes they are more receptive in the afternoon. A classic time is over a meal.
In many situations, we jump in with both feet and try to 'wing it', making things up as we go along. We often default to our preferred style and use patterns of persuasion that may have worked for us in the past (or not).
Invention is going slow to go fast. By doing sound research and deep thinking first about both their and your situation, you have the basis to build a solid argument. You will also be able to present it in a way that will achieve your persuasive goals.
In the original Latin text, this is 'inventio'.