This post explains the method I use for creating the mixed media works.
I take a lot of pictures. I take photos with my phone when I am walking or driving, and I see something that I know intuitively will work well as a painting.
When I start a painting, I go through all of my photos and choose one. I edit and crop the picture on my computer so it will fit on the canvas the way I want it to. I do this process for all of my works, not only for the mixed media works. I like tweaking photos to maximize the effect that I want the painting to have. Here is an example of a painting I did where I spent a lot time finding the "perfect" edit. I wanted the figure to be slightly off center so the folds in her robe would be emphasized. I like having figures slightly cropped so their bodies are pushing off the edge of the canvas, thus not revealing all of the figure. I think this creates a little bit of tension and therefore makes for better composition.
Once I have the perfect photo, I do a line drawing of it on an 11x14" sheet of acetate, which is the same thing as a clear transparency. I use the Sakura Pigma Micron pens in sizes 1 and 3.