I just finished up a studio painting workshop here in Virginia. These are the 1 hour demos I did each day. Demos are a great visual tool to convey the information I discuss with students during class. When I started teaching one of the rules I made for myself was to train myself to demo every day in a reasonable amount of time so students still have plenty of time to work on their own problem solving during the class. Each class is different sometimes the class is an outdoor painting class and sometimes it is focused on studio painting. Each of those situations have their own set of challenges.
When I was taking lots of classes I found it frustrating that some teachers could not or would not demo in class so I made sure I did when I started teaching workshops. I also didn't like teachers who showed up with a finished painting in class and pretended to paint on it for students. I believe working from blank canvas to finish on a painting for students is one of the best tools a teacher has for conveying the art process.
In each demo I focus on a different aspect of problem solving using my approach to the subject. These are always geared towards the students interest and so the demos vary greatly from workshop to workshop. In this instance the things people were most interested in were forest interiors, water and trees without any foliage on them.