We started by painting a layer of glue onto the outside of the snack cup, then put on a layer of tissue paper, followed by another layer of glue. (kiwico.com)
I typically start with 180 grit, down to 150 if its not releasing fast enough 220 if I have a real sheer paint layer over top. (fabulousfinishes.wordpress.com)
The canvas normally has one or more preparation layers applied to its surface before the various paint layers are applied. (sarinadiakos.com)