Hello to Rachel,
Are you restricted to paper mache only? I find with the older students that plaster cast gauze is more interesting to them. Either way, start with a look at the history of masks, the various cultures, time periods and reasons they were used. Then I have students sketch various mask designs exploring different facial expressions. Finally they construct their mask based on a specific theme they have chosen. I also have them write an explanation, description.
Vicki in TN