Red/brown earthenware is a nightmare to clean up and stains everything! I'd stick to clay if I were you.
You definitely need some one session projects so that the students get to see results quickly - certainly in the beginning! It keeps them interested if they get to see a finished pieces quite quickly initially. They'll be happier to take longer over subsequent projects.
Try every idea out yourself first - you'll work out the difficulties in advance AND have a finished product as a teaching aid and motivator for the students! Have an 'extension' activity/idea up your sleeve for students who whizz through at a record pace - there's always one!
Don't underestimate the time it takes to clear up - get the students into good habits and be a good timekeeper yourself, otherwise you'll spend more time clearing up than you do teaching!
Agree with the 'candling' in the kiln suggested above. The one and only time I had work 'explode' in the kiln was because I'd been in too much of a hurry and a piece wasn't completely dry.
Good luck and enjoy!
- Min likes this