just get them to say yes to something
You'll be familiar with Cialdini's Principles of Persuasion.
This clip from the movie Boiler Room, featuring Ben Affleck illustrates his principle of 'commitment and consistency'.
The idea being this; if people can be nudged to commit, ie say 'yes' or agree, to a particular idea in advance, they are more likely to honor that commitment.
It has become accordant with their self-image.
Most people would rather have a reputation for conscientiousness.
Either way, it's a personality trait that is often advantageous to display.
(A bit like authenticity.
Once you can fake that, you've got it made.)
Even when original incentive or motivation is removed they will tend to honor the agreement.
Even better, encourage your subjects to agree a smaller request before being hit with the bigger one.
Potential buyers are more likely to say yes to buying if they’ve answered in affirmative to something else.
Indeed, even eliciting 'yes' responses to seemingly irrelevant questions upfront can still trigger the effect.
Affleck's character Jim Young - one of the co-founders of the brokerage firm J.T. Marlin - is giving a rocket to junior brokers on closing.
'Ask rhetorical questions.
Anything. Just get them to say yes to something.
If you're drowning and I threw you a life-jacket, would you grab it?'
If a potential buyer is on a landing page with their credit card out they are ready to buy.
Just get them saying yes to something.