I believe that well understanding of human anatomy will help a lot in doing figure drawing. So, I always tell my students drawing from inside out. That means the structure of the skeleton beneath the flesh is also important before you try to depict the muscles showing on the surface. Therefore, the anatomy books should be on your hands if you want to sharp your figure drawing skill. Most of these drawings were done in short amount of time about 7 to 10 minutes. Drawing fast, I could let the lines flow and carry the rhythm of energy. That's fun!