This week I did what you suggested and went into photoshop and overlapped some picture. Im using my friend as my reference and I asked her to send me a video of her in fear looking from to side. I took that video and took screenshots from it because I wanted to use specific angles and put them into photoshop and changed the opacity. She sent me two video so I took screenshots from videos and played around with them and saw which one I liked more. I also turned the images to black and white so it can be easier when it comes to drawing it.