Here's a no brainer, when you can't find an available model look for a mirror. I have done a lot of self portraits over the years. I try to accomplish a couple of things in doing them. One is to keep my hand moving and continue to learn to see. Two, I try to communicate something about my thinking or feeling at the moment, to somehow get across where I am in life or how I am in the moment. When I went to the High School of Art and Design I was fortunate to have Irwin Greenberg as my instructor, ( he latter taught at the School of Visual Arts and also at the Art Students League), He would encourage his students to spend time in front of the Rembrandt self portrait at the Met. He would say that the portrait would talk to him in a calming , reassuring way, as if the artist transferred enough of his character into the painting so that you would be able to feel his presence as you stand before the work.