When drawing real people, when you have a partner or a poser that you use as guide for your realism or fantasy drawing. If you like real people to pose for you, but when you don't have anyone to pose for you, you can you the photographs of people. There is some great materials that you can use is called the Virtual Pose. You can get any kind of poses that you ever wanted.
I am using it, and it's great material. When I was taking are classes I always wanted the real deal in front of me. But right now it's much easier for me. I am saving my time and other people time. Make you choice :)Create Effective Drawings
Cartoons and Caricatures