Approximately 65,000,000 years ago, as pterodactyls were on their way out and USB devices were on their way in, printer cables were sold separately from home printers. That was standard practice. Here's how it worked:
You bought a printer from an electronics retailer or your local computer store, you took it home and eagerly removed it from the Styrofoam packaging, dreaming about the convenience of having a home printer. Just as you were ready to connect it to your PC…what the? Where's the printer cable? You searched the contents of the box, astonished to find that the most crucial component of the entire printing process was missing. You knew at that moment that another trip to the computer store would be required.
Here's what was absolutely criminal about the whole situation: the person who rang up your purchase, the person who let you leave the store without a printer cable to accompany your printer, knew that printer cables were sold separately! Why didn't that person say something to you?
Because we live in a just world, most of those retail cashiers are now doing hard time behind bars in the maximum security penitentiaries where they belong.
The point is this: to provide total service to people who purchased a printer, you had to ask them if they also needed a printer cable. Maybe some folks didn't need one: maybe they were buying a new printer to replace their old one and they could reuse the old cable they had purchased previously.
You can bet, however, that every single person who purchased a printer would have appreciated being asked if they needed a printer cable.
What they would have appreciated was the total service they were receiving. They would have appreciated someone smart enough, kind enough and proactive enough to cross-sell printer cables.
Because you know more about your company's products and services than your customers do, it's your duty to inform them about opportunities from which you think they could benefit.
How do you do this? Easy: just tell people what you would want to know if you were the customer. Let them know "what goes with what" or what's on special that might relate to their intended purchase. People sincerely appreciate "real-time customer service" and cross-selling just might be another expression of that philosophy.
Explain the value of your suggestion so the customer see's the connection.
Ultimately, it's the customer's decision to purchase your suggested services or products, or not to purchase them. Don't push anything on anybody; you simply want your customers to know what's available.
Call it cross-selling, call it a logical suggestion, call it what you will: we refer to this customer service skill as offering total service, and it's one way that successful businesses distinguish themselves from their competition.