It is my opinion that in order to have fluid organic animation , your graph editor must have clean, organized curves. Working simultaneously in the viewport,taking careful notice of the spacing, and checking the curves in your graph editor, you can assure to your self that you can obtain nice arcs and animation that flows from one pose to the next.
You can control the snappiness of the animation by how you slow in and out of your extreme poses.
Using tools like ATools makes sculpting your curves easier especially if you have blocked out your scene to as low as 2's 3 's and 4 's on the time line.
Dirty graph editor after conversion to spline from stepped