It's hard to get people to sit still long enough to draw them properly. It's a shame that the few times I feel well enough to try and accomplish this my vision is usually too blurry to take advantage of this stillness. I have grown used to compensating for the motion of both my vision and other people, and developed a style of blurry rendering. It's a funny process where you keep adding to the picture lines and shapes you see, even though the specific angle and position of what I'm drawing keeps changing. Sort of filling in the gaps of reality with what passes for my imagination. As with many things, perseverance and somewhat deluded confidence is essential to anything turning out properly.