1. When you make your first sale, follow-up with the customer. You could follow-up with a "thank you" Email and include an advertisement for other products you sell. You could follow-up every few months. 2. You could up sell to your customers. When they're at your order page, tell them about a few extra related products you have for sale. They could just add it to their original order. 3. Tell your customers if they refer four customers to your web site, they will receive a full rebate of t.