Most sellers on Fiverr hope to make sales, deliver the order and earn a nice review. It's not as easy as it sounds. Most buyers are becoming more harder to please and you'll need to up your game to make long term relationships with them. One way is to OVER DELIVER. Never give $4 worth of service to your buyer. Aim to deliver a $10+ service even though you only charge $5.
If you start to over deliver, give bonuses and treat your buyers in a friendly manner, not only will they give you a positive review but they will become loyal returning customers who may spend 100s of dollars every month on your service.