without knowing exactly the specific needs of creating a new acc on etsy, i think you can follow the general routine what you'd follow on any site where you create a new account, which you want to manage through your browser:
1. purchase a private proxy, configure it in firefox+foxyproxy, make sure that you did it right on a site like ipchicken.com, create a rule in foxyproxy to use the proxy only on etsy
2. delete cookies/flash cookies/cache in your browser
3. use a fully new identity when register a new account (name, email address, profile pic etc.)
4. don't use the same website, again what you promoted on the banned acc, if there was any
(5. if you used the mobile app, maybe it's better if you don't use it anymore or use it only on an entirely different device, because i'm pretty, you will find it difficult to change the device id and use the proxy on your mobile)
+1 never ever try to login to the banned acc