If you use PhotoShop, you can easily create a label preview with an automated action script,
found here on-site.
If you don't use PS, or you just like to do things manually, this template will allow you to easily create a properly sized hi-res image, plus a matching preview image with a 3D center hole and edge treatment. The tutorial itself is printed right on the background of the template, so it's hard to forget ;)
The rar file includes the template with tutorial in PSD format.