I like to convey the character’s inner thoughts with posing. For instance, the character might be feeling something but not showing it in an obvious way. Maybe the face will say “mad,” but the body pose is a bit frightened, or maybe the reverse. For example, think about a mother who just found her child who had wandered off in a crowded area. Her body language might show relief, but her face might show anger. Choosing the poses carefully will go a long way, helping your character communicate complex inner feelings and depth.
I learned from Mark Behm, one of my mentors at Animation Mentor, to always write the emotions (or thoughts) out in words near your thumbnails while you are deciding on poses and planning your scene. It is a constant reminder of the goal of your posing. I can't say how many times I got into a pose and started working on a cool idea, then looked over at the word written next to my thumbnails and realized that the pose I had drawn was not communicating the original emotion. I had gotten wrapped up in creating an interesting pose and lost focus of the bigger picture. Having the emotions written out helped me to quickly make the necessary adjustments and correct the poses. Mark Behm advised me to go through this process every time, no matter how redundant it seemed. And then he disappeared in a puff of ninja smoke.