I'm fairly new to Etsy, and just joined this team today. I have been dealing with the same issue. I have 30 sales, and have only received 5 feedback (100% positive). I have sold things through eBay for a while now, and the feedback rate has been much higher. I think it may be because eBay uses notifications on the main page to remind people to leave feedback, where her on Etsy, I had to actually dig around for a while in order to figure out how to leave feedback. I haven't figured out a way to encourage customers to leave feedback, but would be more than receptive to any suggestions others have found helpful.