Charcoal on 9x12 paper. I did these exercises for about 15-20 minutes each at the hospital where I work during downtime. In drawing figures I don't always have to start the head down to the toes, rather I start at whichever part of the body that strikes me most. For example, I started the first one on top with the left thigh raised up then went down to the feet, then worked my way up again. With the second one directly above, I began with the hip then down to the toes, then worked way up to the head.
It is always easy to start with "blocking" the whole drawing to guide your parameter, then break them down into small "envelopes". Be aware of the "negative spaces" and eyeball constantly the horizontal and vertical lenght of each part that will guide your proportions. You'll be surprise that you won't have the need for the eraser. Always start light then put more pressure on your pencil for the final drawing. In my experience, at first, drawing figures feels like so technical, but when I got my groove going, it paved to creating more of my expression more than anything else. I have been trying emulate styles of some of the professional artists that I like, hoping that I could come up with something interestingly good. Again, I realized that there's no dead end in the road to learning.