Head and Shoulders Don't Turn at the Same Time

Animator's Survival Kit

One of the most common mistakes that junior animators make is to animate a character turning all at once, moving the head and shoulders at the same time. The result is that the motion feels stiff and robotic.

The solution is to offset the body parts so that you either lead with one part - perhaps the head - and then the other parts follow.

The head can lead, and the shoulders follows, or the shoulders lead, and the head follows, whatever feels most natural. The trick is to break up the action so that the different body parts overlap one another, creating the illusion of flexibility and overlapping body parts, or "successive breaking of joints", as Art Babbitt used to call it.