Your customer can log into her account. At the top right hand corner, she will find several icons. The second icon from right to left reads “You”, she should press the arrow that appears under that icon, a drop-down menu will appear. After “Conversations”, there is a “Purchases and Reviews” link. She can click on that link. Her list of purchases will appear. If enough time has passed, her purchase from you will have a “Review This Item” title on a blue background. There are five grayed-out stars. She can click on the star the best describes her satisfaction with your item (five starts means "completely satisfied") and then leave a review on the window that pops-up after she clicks on the star of her preference. When she is done, she can click on the “Post Your Review” button. I hope this helps
