One time I actually gave a kid a lesson in sales.
"Um hi do you want to buy some cookies."
"No no no, kid, you're doing it all wrong. First rule of sales, only ask a question that you know the customer already knows the answer to. So try something like 'hi mister, would you like to help me do something cool?' Then of course I say 'yes.' Then you can jump in with the candy or cookies or whatever it is, and be sure to explain how by buying the cookies actually helps you accomplish the cool thing."
I made him practice his pitch to me.
Of course then I told him no I don't want your stupid cookies and to get lost. (jk

)