If you miss the line of action you will probably be disappointed in your finished drawing.
It is particularly important that you find the swing of the body in seated poses. If you stress the line of action in seated figures, they will appear more life-like. To those whose knowledge of anatomy is not yet too advanced I would say that there is nothing that will do more to improve your figure drawings than to stress the action. Exaggerate the action if necessary!
If you are lucky enough to have a model, pose her so as to show a definite line of action, or else exaggerate the action that you do see in the pose.
If the model is leaning, maker lean over more! As you can see, in this pose I exaggerated the line of action that was not too apparent in the model’s actual pose. I made her body look more relaxed by drawing her as if she were really leaning on that arm.
Decide what is most characteristic about a pose, then make it do more. On the above example, the most obvious characteristic of the pose is that is a relaxed pose, a “sleepy” pose – the model could fall asleep in a pose like that. Therefore, I drew it so as to give that effect.
On this page, the pose is inherently an alert one. So I’ve made it more alert – I’ve pup “pep” into it! It is up to you to judge what the action is in each pose that you draw. But do make some decision – and make it obvious in your drawing. Right or wrong, don’t be hesitant. Draw in the line of action you think yo see, then stick to it and exaggerate it if necessary.
The difference in the exaggerated pose is slight, but very important.
Here is an exaggerated line of action for a great effect.
If you want to see more about better figure drawing, there is an e-book version here.