I repeatedly harp on feeling the pose rather than merely looking at it. By only looking at it, you have to keep looking at it repeatedly as you copy the parts. In feeling the pose you actually picture yourself as doing the pose. If you have to, stand up, put down your drawing board, and assume the pose. Feel which muscles pull or contract to get which stretch or squash. Feel where the weight falls, what is entailed to keep your balance. Feel the psychological attitude it imparts, i.e., if the head is drooped, does it evoke a sad or disappointed feeling; if the head is held high, do you feel proud or haughty or reverent — or what? So with the whole body impose some kind of attitude on it. Then you have that pose locked into your mind and can summon it up at will by simply seeing it in your mind and assuming that attitude. As a matter of fact you can see it from any vantage point — you could even do some mental levitation and look down on it from above.
Contrast that approach with the slow and ponderous neck-tiring process of looking at the model, noticing the angle of the upper arm, looking back to the paper and sketching in the upper arm, then looking at the model to see what the lower arm is doing, then back to the paper to sketch that in, then back to the model to search out the next thing to draw, then back to the paper to see if what you have already drawn will give you a clue to what to add next, and so on, etc.
The “feeling the pose” method is of great help during live sketching where you have an awkward view of the model, say, a view where one leg and one arm are hidden from your view. With the live model the pose is somewhat clear because there are dozens of telltale indications of what is going on, but these illusive indications are difficult to capture in a line drawing. However, if you lock into the pose, you can make the necessary adjustments required to clarify it. After all, in animation you would have to do that. You go to great lengths to get everything out in the open to make your pose “readable” — so why not in a practice session. I’m sure you all know how to fantasize so put it to use in drawing. If you can lock into the pose you can also fantasize the pose into useful variations, which sounds a little like animating.