Create a referral incentive program: a client who refers another client to you receives an automatic 15 % discount the next time he uses your service (which also encourages repeat business). (slaw.ca)
A rating system allows users to be reviewed, which helps encourage repeat business. (creativeboom.com)
Loyalty is often rewarded in the travel business, with most airlines, hotels, and car rental agencies offering travel cards to encourage repeat business in exchange for discounts, upgrades, perks, and member status. (travelandleisure.com)