I always have students use the outside of the molds, and put down a paper
towel first, then the plaster strips. This seems to create a nice smooth look.
Don't forget to tell them to smooth out the little air holes to make a seamless
When painting, have them do sketches first so they know exactly what color
scheme they will be doing. Remind them they have to put one layer of color down
first- or two, if they are splitting the face in half, etc...then let that
dry before applying details etc. A lot of times they want to jump in and add
all the details when paint is still wet.