You can start a referral program by recruiting some of the customers as influencers. Before starting with the program make sure your brand message is easy to understand and convey. Start this program by building a community around your brand. This type of marketing is more than a product and a logo, let them talk about the service, working etc. Note that your customers are your best salespeople. Customers would get most attracted to a product when they would see the satisfaction derived by the customers who have already used it. To make the process efficient try to make referrals easy.