One thing animators do is act out scenes and photograph themselves. You can do this, or have a model act out a scene when you' are taking reference. One story Norman Rockwell talks about in his autobiography involves a teacher coming up to him and asking what he is drawing. I'm paraphrasing here as I don't have the book with me at the moment, but Rockwell says he is drawing a kid fishing. The teacher asks, "Why does he need to catch a fish? Does his father beat him if he doesn't? You have to know." This stuck with Rockwell and I think contributed to why his paintings are so well thought out. Take "Homecoming Marine", which is one of my favorites. Notice how everyone is leaned in, seemingly hanging on every word. Also notice how the small boy is sitting so close to the Marine that their legs touch. Generally, we only let family members into our personal space that way. Rockwell's characters aren't just posing--they're acting. I think this is what separates Rockwell from other artists that have the technical skill, but lack the ability to bring the subject's thoughts and feelings to the surface. I've seen many a painting that is technically accurate, but nevertheless looks as if someone is posing in a studio in a costume. If you like to read, I would suggest "Acting: The First Six Lessons" by Richard Boleslavsky. It will give you insights into the craft of acting and can help you pose your characters in ways that communicate what they are thinking and feeling.

I'm not sure what you mean by "Body Language"? Do you mean how to express a character through their poses? If so, there is a lot to talk about there. I just gave a lecture on it to my storyboard class. To break it down into quick tips: 1- Give the pose a clear line of action. 2- Give the pose a strong silhouette. If the drawing was filled in with solid black and no details were visible you should still have some idea what the character is doing. 3 - The hierarchy of expressiveness in a pose is eyes, face, hand, entire rest of the body. This means that the eyes are the most expressive part, followed by the face and so forth. 4 - The eye mask is the area of the face and eyes including the eyes, eyelids, eyebrows and upper cheeks, make sure this area is expressive. 5 - Eye direction is important to make a character look like they are thinking. Make sure the character is looking at what is important to them. 6 - Exaggerate the pose and expressions. Make the story and emotional purpose of the pose as clear as possible.

Hi greenleaf. I would recommend to view the proko gesture drawing course :)