When you eat at a sit-down restaurant, it’s common knowledge that you should tip the server. Sure, some restaurants print a suggested tip amount on the receipt, though I believe this is mainly to encourage larger tips or make the calculations easier. But what about other businesses where the protocol for tipping isn’t established yet, or people aren’t familiar with it?

Take grocery delivery, for instance. Peapod makes it very clear that tips are optional. But by simply mentioning tips in the first place — and making it easy to add a tip with a credit card — I bet they convince at least half of their customers to tip the delivery person. This doesn’t address the question of how much, though. One person might tip a dollar or two, while another might use 10-15% of the order value.

The best approach would be to give customers the relevant info about tipping, without being too pushy. For instance, the order confirmation email might say something like this: “Tipping your delivery person is optional. When our customers choose to leave a tip, they typically calculate it based on 5-10% of the order amount. If you don’t feel comfortable leaving a tip, you can still help out our staff by telling your friends and colleagues how much you’ve enjoyed our service.” By providing some parameters for suggested tip amounts and an alternative, non-monetary action, you’ll make all of your customers feel at ease. At the same time, you’ll be promoting larger tips and encouraging word of mouth marketing that helps grow the business as a whole.