Introduce yourself the the "customer" - Hi, I'm bla bla bla, im going to sell you shiii... Ask questions..."what kind of dispenser do you have now?" "what do you find important in a dispenser?"... Recommend the item you are selling, based on what you now know of the "customer" - "I know you need double sided tape that is reliably sticky, at an affordable price, you should check out this brand." Ask them if they want to buy it, by saying- "do you want me to ring this up?" or "do you want this black one, or would you like the white one from the back room?"