Cross-selling is the practice of selling additional products or services to an existing customer. It is a strategy used to increase customer spend and lifetime value, as well as loyalty and customer satisfaction. There are many ways to cross-sell, but it generally involves identifying complementary products or services that would benefit the customer, and then making a recommendation. For example, a mobile phone company might cross-sell insurance for accidental damage, or a clothing retailer might upsell customers from basic items to more premium brands.