There is a children’s book called “Fox Tale Soup“. This is the old story of Stone Soup retold with Fox and farm animals. If you have not read the original I recommend reading this version.
The clever Fox is a great influencer. He starts out by asking for food but was denied any help by the farm animals. After being rejected for his initial request the fox starts with a trivial request,
“just some water please, after all I got the stone to make stone soup”
One of the animals yield and bring water. Of course, if only there was some seasoning, some potato, some rutabaga, …
The fox slowly builds on his seemingly trivial request for water to get to all the ingredients for the soup. The farm animals one after the other ends up bringing salt, potato, rutabaga etc. There are multiple influence principles at play here.
The fox started with an outrageous request, asking for food. Since he was a total stranger the animals so the animals were right in rejecting his request.
Then he followed up with a trivial request, water, which is available in plenty. This is anchoring.
Once the animal agreed and brought water, there eas no turning back. They ended up giving the rest of the ingredients because of the power of commitment and the inherent need in us to act consistent to our past actions (consistency principle).
There was also consensus effect. Since other animals were helping the fox, any animal that had any misgivings about not helping the fox were nudged by the actions of others and were convinced to help.
That is the power of persuasion.
If you want the psychology behind this you should also read, Influence: The Psychology of Persuasion by Robert Cialdini.
Other book I recommend is Nudge by Sunstein and Thaler.