Make the other person feel important - and do it sincerely
In [@carnegie2010How to win friends & influence people], the author suggests that the best way to gain someone's time and attention is by making them feel important. He gives as an example a person who visits a busy businessman, who never had meetings of over 15 minutes. This person, instead of cutting to the chase, he realizes the office is covered in wood and very impressive. Therefore, he starts loathing the woodwork, etc. Of course this lead to a bigger deal, etc.
Carnegie says that making someone feel important can even work with someone who is already famous, and cites the anecdote of someone who wrote to a British poet about how good his work was. There are other examples, but the most important thing is that making someone feel important is not flattery. That's why it is mentioned that it should be sincere.
Sometimes we are in positions of power (think a teacher in a class), in which making someone feel important is relatively similar to: Give honest and sincere appreciation.
Literature note on: The Leader in You - Dale Carnegie