I haven't been here in awhile, so I hope this is okay to share. For the last pet portrait I completed, I set up my Nikon D7000 and filmed, starting with the drawing already completed (monochrome underpainting) to the completed piece. My son helped me create a video from the footage (slightly more than 3 minutes), complete with a favorite Mozart song.
If you woud like to see the brief video, you can find it on Youtube:
https://www.youtube.com/watch?v=A0niGTrvMNc
I also filmed part of my last portrait commission (just delivered, a young woman) which I hope to post next as a speed painting demo.
It was a fun project to make this video and I thought some of you might enjoy doing something similar as a way to market your work.