The most essential skills for making 3D animation are the comprehensive skills needed for animation software such as Maya or 3ds Max. These skills include creating 3D models, textures, lighting, other visual effects, and the animation itself through keyframing and/or motion capture.
Additional artistic and soft skills will also help. Understanding the principles of animation in general—like timing, spacing, anticipation, and squash-and-stretch—will apply to 3D animation specifically, as will a knack for drawing, visual composition, color, and design. Attention to detail and soft skills like problem-solving and good team communication are also important.