Aristotle said that to be persuasive, you must have the ability to move an audience emotionally, because people often do not make decisions logically.
As I mentioned in a recent post, one way to tap emotions is through flattery. Another tactic is to ask for things in increments, starting with a small initial request.
Let’s say that in three months you plan to ask your colleague Cindy to manage an important project, but you are unsure if she will agree to do it. You are more likely to persuade her to take on that role if you move toward the goal gradually. You might start by periodically asking Cindy for her opinion on topics or issues that arise relating to the project. Then ask her to attend a meeting. Having already played an initial “role” by contributing her expertise, she is more likely to agree to attend the meeting. Eventually, you ask her to lead the project.
In social psychology, this is called the foot-in-the-door technique. Make a small request initially, thereby getting your “foot in the door,” and then return with a larger request. Political campaign staffs use this approach. Organizers will ask a potential supporter to read a brochure about the candidate and a couple of position statements. Then they will ask that person to attend an event, and later will ask if the person is willing to host a fundraiser. The target of the persuasive appeal is more likely to agree to the larger request because people like to be consistent in their behavior. If they did it once, they are inclined to agree to a subsequent request.
If you are asking management for a training program that is costly, try asking for less initially, perhaps a pilot program. If it is successful, return with a request for the full program, and your chances for approval are significantly higher. The initial, smaller request is less intimidating and less risky to your audience, so they are more likely to agree to it. Then, having said yes once, they are more likely to agree to the larger request.