A place where I worked for six weeks. During that time I was taught their time tested method for selling lots of artery clogging goodness which I plan on sharing with you right now:

Step 1:
Great the customer with a hearty full toothed smile and proudly exclaim "Hi, I'm YourNameHere. Can I interest you in some hot fresh popcorn topped with something that has the consistency of hot grease and tastes a little like butter?"
Step 2:
Get their order. If they ask for a small, get them to buy a medium. If they buy a medium, get them to buy a large. This is called upselling, or attempting to convince your gullible ass that you need a huge tub of stale popcorn and a huge cup of sugar water that doesn't fit in the drink holders.
Step 3:
Attempt to talk the customer into buying just one more item. Their biggest suggestion here was that if the customer has children, to stare directly at them and say "Hi Kids. Would you like some candy? We've got a ton of it... it's all right here inside this brightly colored case."
Step 4:
Take the money. Give the person their change.
Step 5: