Cross-selling is a sales tactic where you suggest additional, related products when a customer is about to make a purchase. Instead of upgrading what they're buying, you're adding more items to the cart. It's the digital equivalent of "Would you like fries with that?"
Picture this: you're buying a smartphone online. You reach the checkout page and see suggestions for a screen protector, phone case, and earphones. You think, "Yeah, I'll need those anyway," and add them to your order. That's textbook cross-selling. The retailer just increased their revenue per transaction by suggesting complementary products.
Cross-selling is incredibly effective because it capitalizes on the customer's existing buying intent. They're already committed to purchasing, so adding related items feels natural rather than pushy. This strategy works both online and offline. Walk into a clothing store and the sales associate will suggest shoes or a belt to match your shirt — same principle. When done well, cross-selling boosts both your AOV and customer satisfaction, since you're genuinely helping them find everything they need.